Future-Proofing Fuel Cells: Critical Raw Material Governance in Sustainable Energy 3030768058, 9783030768058

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Future-Proofing Fuel Cells Critical Raw Material Governance in Sustainable Energy Martin David · Stephen M. Lyth Robert Lindner · George F. Harrington

Future-Proofing Fuel Cells

Martin David • Stephen M. Lyth Robert Lindner • George F. Harrington

Future-Proofing Fuel Cells Critical Raw Material Governance in Sustainable Energy

Martin David Leuphana University of Lüneburg Lüneburg, Germany Robert Lindner Platform of Inter/Transdisciplinary Energy Research (Q-PIT) Kyushu University Fukuoka, Japan

Stephen M. Lyth Platform of Inter/Transdisciplinary Energy Research (Q-PIT) Kyushu University Fukuoka, Japan George F. Harrington Next-Generation Fuel Cell Research Center (NEXT-FC) Kyushu University Fukuoka, Japan

ISBN 978-3-030-76805-8    ISBN 978-3-030-76806-5 (eBook) https://doi.org/10.1007/978-3-030-76806-5 © The Editor(s) (if applicable) and The Author(s), under exclusive licence to Springer Nature Switzerland AG 2021 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the ­publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and ­institutional affiliations. Cover illustration: Maram_shutterstock.com This Palgrave Macmillan imprint is published by the registered company Springer Nature Switzerland AG. The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

Foreword

The concept for this book project grew out of a mutual recognition for the need of stronger interdisciplinary collaboration in sustainable energy studies. It is the result of in-depth discussions about early stage fuel cell technology governance between scientists from very different disciplinary backgrounds, broadly including materials science, engineering, sociology, and political science (although it should be noted that disciplinary labels are becoming less relevant in modern academia). In particular, an interdisciplinary “back casting” exercise crystalized some of the concepts that are followed through in this book. During these exchanges the need to “translate” disciplinary language and jargon for a non-specialist audience was quickly realized, as well as the need to develop a common analytical framework to enable a fruitful interdisciplinary collaboration. This is reflected in the structure of the book, which introduces the reader to relevant aspects of fuel cells, critical raw materials (CRMs), and governance in short, dedicated chapters in a way that is hopefully understandable to different portions of the disciplinary spectrum. This approach of course has limitations, since the scope is rendered by only four individuals and does not allow for active participation from other actors. While we acknowledge these shortcomings, we hope this text provokes a more profound discussion on anticipative governance strategies to address CRM issues in future sociotechnical pathways related to fuel cells. Fukuoka, Japan Stephen M. Lyth

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Contents

1 Introduction  1 1.1 Climate Change and Decarbonization  1 1.2 Electrification and Energy Storage  2 1.3 Critical Raw Materials  4 1.4 The Hydrogen Economy  6 1.5 Fuel Cells  9 1.6 Critical Raw Materials in Fuel Cells  9 1.7 Governance of CRMs 10 1.8 Structure of This Book 11 References 11 2 Critical Raw Materials 15 2.1 Defining CRMs 15 2.2 CRMs in Sustainable Energy Technologies 18 2.3 Case Study: Cobalt in Lithium-Ion Batteries 21 2.4 Factors Increasing CRM Supply Risks 22 2.5 The EU Action Plan on CRMs 25 2.6 CRMs in Fuel Cell Technologies 26 2.7 Future-Proofing Fuel Cells 27 References 27 3 Critical Raw Materials in Polymer Electrolyte Fuel Cells 35 3.1 What is a Polymer Electrolyte Fuel Cell? 35 3.2 History of PEFCs 38 vii

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3.3 Modern Fuel Cell Electric Vehicles (FCEVs) 39 3.4 Comparing PEFCs and Li-Ion Batteries 42 3.5 Platinum in PEFCs 45 3.6 CRM Avoidance in PEFCs 47 3.7 Ultra-Low Platinum Loading 49 3.8 Platinum Nanoparticle Shape Control 50 3.9 Platinum Alloys 51 3.10 Issues with Decreasing the Platinum Loading 51 3.11 Recycling 52 3.12 Platinum-Free Catalysts 52 3.13 Chapter Conclusion 53 References 53 4 Critical Raw Materials in Solid Oxide Fuel Cells 57 4.1 History and Overview of Solid Oxide Fuel Cells (SOFCs) 57 4.1.1 Early Development 57 4.1.2 Operating Principles and Components 58 4.1.3 Advantages and Disadvantages 60 4.2 Material Choices in SOFCs 62 4.2.1 Electrolytes 62 4.2.2 Cathodes 63 4.2.3 Anodes 64 4.2.4 Interconnects 65 4.2.5 Geometries and Fabrication 65 4.3 Commercial Production and Applications of SOFCs 67 4.3.1 Portable Electronics Battery Replacements 67 4.3.2 Residential: Combined Heat and Power Systems 67 4.3.3 Automotive: Fuel Cell Vehicles (FCVs)/Range Extenders for Battery Electric Vehicles (BEVs) 68 4.3.4 Auxiliary Power Units for Commercial or Industrial Enterprises 69 4.4 Criticality of Materials for SOFCs 69 4.5 SOFC Research, Development, and Mitigation Strategies for CRM Use 74 4.5.1 Key Benchmarks and Targets 74 4.5.2 Development of Alternative Materials 75 4.5.3 Strategies for Reduced Usage 76 4.5.4 Recycling 76

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4.6 Chapter Conclusion 77 References 78 5 Technology Governance 83 5.1 What Is Technology Governance? 83 5.2 CRM Governance in Sustainable Technologies 86 5.3 Introducing a Research-Oriented Anticipative Governance Approach 88 5.3.1 Foresight 90 5.3.2 Engagement 92 5.3.3 Integration 93 5.4 Chapter Conclusion 94 References 94 6 The Case for Governance of Critical Raw Materials in Fuel Cell Research and Development 99 6.1 The Need for Anticipative Governance in Fuel Cell Research and Development 99 6.2 The Fuel Cell Research and Development Spectrum101 6.3 An Anticipative Governance Approach to Fuel Cell Research and Development104 6.3.1 Foresight: Awareness of CRM-Related Issues104 6.3.2 Actor Engagement: Communication Between Researchers107 6.3.3 Integration: Tools for Managing Fuel Cell Research and Development108 6.4 Chapter Conclusion113 References113 7 Practical Recommendations and Conclusion119 7.1 Incentives120 7.1.1 Increased Funding and New Funding Avenues of Research120 7.1.2 Funding Constraints121 7.1.3 Prizes122 7.2 Education123 7.2.1 Courses Within Higher Education123 7.2.2 Communication Between Actors124

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7.3 Guidelines and Regulation126 7.3.1 Guidelines and Software Tools126 7.3.2 Supplier Selection in Laboratory Procurement127 7.4 Conclusion128 References129 Index131

Abbreviations

(Ca-, Sr-)LaCrO3

Lanthanum Chromite Doped with Either Calcium or Strontium BEV Battery Electric Vehicle CAPEX Capital Expenditure CCS Carbon Capture and Sequestration CGO Gadolinium-Doped Cerium Oxide CH4 Methane CHP Combined Heat and Power CO Carbon Monoxide Co Cobalt CO2 Carbon Dioxide CRM Critical Raw Material DOI U.S. Department of Interior DWSB Bismuth Oxide Doped with Tungsten and Dysprosium Dy Dysprosium ECS Electrochemical Society ESB Bismuth Oxide Doped With Erbium EU European Union FCEV Fuel Cell Electric Vehicle FCH JU Fuel Cells and Hydrogen Joint Undertaking FCV Fuel Cell Vehicle FP7 Seventh Framework Programme for Research and Technological Development Ge Germanium H2 Hydrogen H2O Water IEA International Energy Agency xi

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JSPS Japanese Society for the Promotion of Science LCA Life-Cycle Analysis Li Lithium Li-ion Lithium-Ion LSCF Strontium-Doped Lanthanum Iron Cobaltite LSGM Lanthanum Gallium Oxide Doped with Strontium and Magnesium LSM Strontium-Doped Lanthanum Manganite LST Lanthanum-Doped Strontium Titanate METI Ministry of Economy, Trade and Industry MHPS Mitsubishi Hitachi Power Systems Ltd. MIECs Mixed-Ionic Electronic Conductors MITEI Massachusetts Institute of Technology Energy Initiative MRS Materials Research Society MRV Measurement, Reporting and Verification Tools NASA National Aeronautics and Space Administration Nd Neodymium NGO Non-governmental Organization Ni Nickel O2 Oxygen OECD Organisation for Economic Co-operation and Development OPEX Operational Expenses PEFC Polymer Electrolyte Fuel Cell PGM Platinum Group Metal Q-PIT Platform for Inter- and Transdisciplinary Energy Research RSC Royal Society of Chemistry rSOC Reversible Solid Oxide Cell SDGs Sustainable Development Goals Si Silicon SOEC Solid Oxide Electrolyser Cell SOFC Solid Oxide Fuel Cell TKK Tanaka Kikinzoku Kogyo UN United Nations UNFCCC United Nations Framework Convention on Climate Change US DOE United States Department of Energy WTO World Trade Organization YSZ Yttria-Stabilized Zirconia μSOFC Micro-SOFC

List of Figures

Fig. 1.1

Fig. 1.2 Fig. 2.1 Fig. 2.2 Fig. 2.3 Fig. 2.4 Fig. 2.5 Fig. 3.1 Fig. 3.2 Fig. 3.3 Fig. 3.4

Periodic table showing changes in CRM assessment by the European Commission between 2011 and 2017. (Source: Rizzo, A. et al. (2020): The Critical Raw Materials in Cutting Tools for Machining Applications: A Review. Materials 13/1377: 3. https://doi.org/10.3390/ma13061377 (CC BY 4.0)) Schematic representation of the hydrogen economy. © National Renewable Energy Laboratory Illustration of the current supply risks of selected raw materials for nine key technologies in three different sectors. (Source: EU Commision, 2020e, S. 10) List of CRMs associated with sustainable technologies. (Adapted from EU Commission (2020e)) The number of battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) currently in operation. (Source: IEA (2020)) Regional distribution of CRMs. (Source: EU Commission (2020d, p. 4)) Relevant raw materials used in fuel cells. (Source: EU Commission (2020e, S. 25)) Schematic of a simple polymer electrolyte fuel cell (PEFC) The newly released Toyota MIRAI FCEV. ©Stephen Lyth, 2021 Schematic comparing some of the advantages of FCEVs and BEVs Comparison of the relationship between cost and range for FCEVs and BEVs today, and projected costs for 2040 for (a) cars and (b) trucks (Cano et al., 2018)

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List of Figures

Fig. 3.5 Fig. 3.6 Fig. 4.1

Fig. 4.2 Fig. 4.3 Fig. 4.4 Fig. 6.1

Breakdown of the cost of different components in a fuel cell stack, for production scales of (a) 3000 and (b) 500,000 units per annum. (Source: data taken from Thompson et al., 2018) 45 (a) Transmission of electron micrograph and (b) schematic of a typical platinum-decorated carbon black catalyst used in PEFC research. (Image courtesy of David Rivera, 2018) 49 Schematics of a metal oxide crystal lattice. (a) “Perfect” crystal structure. (b) Crystal structure with oxygen deficiency due to the introduction of a dopant, allowing for oxygen ion transport to take place 58 Schematic of the operational principles and components of an SOFC 59 SOFC designs and geometries 66 Prototypical SOFC designs used to estimate the amounts of CRMs needed for residential, grid-scale, and automotive applications72 The fuel cell development spectrum, demonstrating the range of research being carried out on fuel cell technologies 102

List of Tables

Table 2.1 Table 4.1

Table 5.1 Table 5.2

Critical raw materials 2020 (new as compared to 2017 in bold) The annual amount of raw materials required for the three SOFC designs to satisfy the residential, grid, and automotive applications, compared to the annual production in 2019 (U.S. Geological Survey, 2020). The percentage of annual production required for each application is calculated. The production of each rare earth element is estimated from the average percentage found in mineral deposits (European Union, 2014) combined with total production. Critical raw materials are labelled as defined by the European Union Commission in 2020 (European Commission, 2020) Recent early studies of governance approaches to CRMs, in chronological order Roadmap for a hydrogen society

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73 87 91

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CHAPTER 1

Introduction

1.1   Climate Change and Decarbonization The burning of fossil fuels releases carbon dioxide into the atmosphere. This greenhouse gas causes climate change, which is the biggest threat to the survival of our species. In 1997, the urgency of this issue was recognized at the United Nations Framework Convention on Climate Change (UNFCCC), in the form of the Kyoto Protocol. This formed the cornerstone of international climate policy. In 2015, the international community negotiated the landmark Paris Agreement, which entered into force in 2016 and committed the signatory UN member states to hold “the increase in the global average temperature to well below 2 °C above pre-­ industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels” (UNFCCC, 2015, S. 3). Around the same time, the Agenda for Sustainable Development, with its 17 Sustainable Development Goals (SDGs), was agreed upon. SDG 7 was specifically formulated to ensure access to affordable, reliable, sustainable, and modern energy for all people in the world by 2030 (UN, 2015). These agreements have framed current efforts to deploy renewable energy technologies for decarbonization in the ongoing global energy transition. However, progress on decarbonization of the world’s energy systems has been slow, and global energy demand is set to increase even further. The International Energy Agency (IEA) recently stated that “the pace and scale of the global clean energy transition is not in line with climate © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 M. David et al., Future-Proofing Fuel Cells, https://doi.org/10.1007/978-3-030-76806-5_1

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targets” (IEA, 2019a). The IEA also projected an annual increase of around 1% in energy demand until 2040, due to diverse factors such as population growth, economic development, digitalization of services, and increasing efforts to bring modern energy services to the world’s poor (IEA, 2019b). More than 860 million people in the world still don’t have access to electricity and 2.6 billion people rely on the use of biomass for cooking and heating. If the rise in consumption is not met by a simultaneous decarbonization of the energy sector through rapid deployment of modern renewable energy technologies and improvements in energy efficiency, it will be impossible to meet the goals laid out by the Paris Agreement, or to curb the effects of global heating. However, there are also positive indications that a radical shift in the way we produce and consume energy is underway, and that this transition is accelerating (Davidson, 2019; Sovacool, 2016; Sovacool et al., 2020b; GCGET, 2019). Many governments have recently taken the decision to phase out unsustainable forms of energy production from coal and nuclear sources (David, 2018). Moreover, installed renewable energy production capacity has more than doubled in the past ten years, now accounting for a third of the total global power generation capacity (IRENA, 2020a). There have also been important technological improvements on the energy consumption side, such as increasing the use of smart metering and improvements in efficiency (IEA, 2017). Market disruptions caused by the current COVID-19 pandemic may accelerate this process even further, since economic recovery measures through infrastructure investments coincide with renewables having reached cost parity with fossil fuels (IRENA, 2020b).

1.2   Electrification and Energy Storage The most effective way to avoid the combustion of fossil fuels is to utilize renewable energy efficiently through electrification (Ruhnau et al., 2019). However, it remains extremely challenging to fully electrify areas that traditionally employ fossil fuels, such as the transport sector, the heating and cooling sector, and large-scale industrial processes such as cement and steel manufacturing. Whilst the proportion of renewables is increasing, electrification of the above sectors would necessitate a huge increase in the installation of renewables, as well as significant and unfeasibly expensive upgrades to the capacity of global electricity grids. In addition, the intermittency of renewable energy (i.e. balancing the excess power generated

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on windy sunny days with the low amounts of power generated on calm, dark wintery days) would make the management of a fully electrified society extremely problematic (Suberu et al., 2014). An effective large-scale and long-term energy storage medium would go a long way to solving the above issues, enabling us to “save up” excess renewable energy until it is required at a later time, allowing the energy supply to be varied to match the energy demand, known as electric load balancing. However, selecting a suitable technology for the large-scale storage of energy is not a simple matter. The selected technology should fulfil the requirements of efficiency, low cost, scalability, and safety. One traditional example is pumped-storage hydroelectricity. This has served as a large-scale energy storage technique for over 100  years (Rehman & Al-Hadhrami, 2015). In this technology, water is electrically pumped uphill into a dammed reservoir during times of excess power generation, and released to power a turbine when the power is required. This has provided some flexibility in large-scale energy storage and use. However, the potential capacity of suitable sites is limited; the response time is rather slow in terms of grid dynamics (i.e. as long as it takes to open the sluice gates and start their turbines); the building of dams necessitates vast engineering projects; there is significant risk to life in the event of dams failing; and there is a major impact on local ecology (Pérez-Díaz et al., 2015). Today, rechargeable lithium-ion (Li-ion) batteries are a more modern state-of-the-art energy storage medium, first developed commercially by Sony in the 1990s (Blomgren, 2017). Most of us are familiar with small Li-ion batteries in our everyday lives, as they have become omnipresent in powering our phones, laptops, and other small devices. Li-ion batteries are also used for load balancing of for example residential-scale or industrial-­ scale photovoltaic systems (Uddin et al., 2017). Meanwhile, battery electric vehicles (BEVs) such as the Nissan Leaf and the various Tesla models are becoming an increasingly important part of mobility, contributing successfully to electrification of the transport sector. The largest battery in the world is currently in operation in Hornsdale in South Australia, developed and installed in 2017 by Tesla. This colossal battery is used to balance power from a large wind farm, and serves to stabilize the power grid, preventing surges and ultimately saving the Australian government $116 million in 2019. A second battery with more than double the capacity is planned to be installed by the renewable energy company Neoen, near Geelong (Morton, 2020). This new battery will be able to power around 500,000 homes for around 30 minutes, and even

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larger projects are planned for California and New York. However, these giant Li-ion batteries are not suitable for storing energy over longer time periods, due to their limited capacity. Li-ion batteries undeniably offer one of the best routes to decarbonization via electrification in certain sectors. Nevertheless, they are not a panacea to the problems associated with the combustion of fossil fuels. Scale up of Li-ion battery utilization to the levels required to act as a true large-­ scale and long-term seasonal energy storage medium would require vast economic investment and immense materials resources. In addition, Li-ion batteries are not physically suited to long-term energy storage over for example seasonal timescales because they gradually lose their charge over time as the stored energy dissipates in a process known as “self-discharge” (Yazami & Reynier, 2002).

1.3   Critical Raw Materials There is a growing awareness that even supposedly “green” renewable energy technologies can struggle with a new kind of “fossilization” (Raman, 2013). Prominent examples are lithium-ion batteries, the magnets used in wind turbines, or photovoltaics, the manufacture of which all depend on so-called critical raw materials (CRMs). Materials can be classed as CRMs if they are economically and strategically important to the economy and/or key industries, but there is a high risk associated with their supply (Ferro & Bonollo, 2019). Specifically, CRMs are a selection of so-­ called rare earth elements, precious metals, and some high demand minerals. Figure  1.1 shows a periodic table highlighting elemental CRMs as classified by the EU. Within this list, Li-ion batteries utilize significant amounts of cobalt (Co) and lithium (Li—added in 2020 list); wind turbines contain neodymium (Nd) and dysprosium (Dy); and photovoltaics contain elements such as silicon (Si) and germanium (Ge). The assessment of CRMs relies both on macro-information of markets, and on information from industrial actors (Choi et al., 2018). These materials are not only characterized by an extreme price volatility, but can also have serious impacts on the environment (e.g. contamination of ground water), to human health (e.g. exposure to toxic materials, unsafe working conditions), and to socio-political systems (e.g. war economies, international conflict, monopolies) (van de Graaf et al., 2020). This presents a challenge to the envisioned global energy transition and points to a dilemma that all new technologies face, namely that their impact cannot

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Fig. 1.1  Periodic table showing changes in CRM assessment by the European Commission between 2011 and 2017. (Source: Rizzo, A. et  al. (2020): The Critical Raw Materials in Cutting Tools for Machining Applications: A Review. Materials 13/1377: 3. https://doi.org/10.3390/ma13061377 (CC BY 4.0))

be fully predicted until after the technology is mature and has reached a certain dissemination level (Collingridge, 1980). However, once a technology reaches maturity, path dependencies can be established. A path dependency is essentially a resistance to change—what happened in the past persists into the present and influences the future. Small decisions taken in the earliest development stages can potentially snowball into enormous global impacts in later stages of product commercialization and mass-market penetration. Once pathway dependencies are established, it can be extremely difficult to switch to alternative solutions which avoid the use of CRMs. However, considerations about sustainable CRM strategies and procurement are not always incorporated into laboratory research and development settings. This applies even more to corporate sector research and development settings, which are largely considered to be a “black box” (Vazquez-Brust et al., 2020). One reason for low awareness may be that

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higher education institutions typically do not include ethical, social, or economic dimensions of CRM use in the curricula of engineers or product designers.

1.4   The Hydrogen Economy A potentially game-changing sustainable energy solution which has gained traction in recent years is the hydrogen economy. Hydrogen is the lightest element in the periodic table and is the most abundant element in the universe. On earth, pure hydrogen usually exists as a gas molecule (dihydrogen, H2). This gas has a very high energy density for its weight. It can be burned with oxygen (O2) to generate power, much in the way fossil fuels such as natural gas (methane, CH4) are burned. The key advantage of burning pure hydrogen over the combustion of fossil fuel “hydrocarbons” is that the former generates only pure water (H2O) (Eq. 1.1), whilst the latter produces both water and carbon dioxide (CO2) (Eq. 1.2). As such, hydrogen can potentially be used to power society without directly emitting CO2 into the atmosphere. This has obvious implications for the reduction of greenhouse gas emissions in line with internationally binding agreements such as the Paris Agreement.

hydrogen ( 2 H 2 ) + oxygen (O2 ) → water ( 2 H 2O )



(1.1)

methane ( CH 4 ) + oxygen ( 2O2 ) → water ( 2 H 2O ) + carbon dioxide ( CO2 ) (1.2)

However, unlike the vast naturally occurring underground reserves of coal, oil, and natural gas, hydrogen gas is not abundant in nature. It can’t be mined, drilled, or extracted from the ground; and it can’t be collected or harnessed like wind or sunlight. Consequently, hydrogen is not classed as an energy source, but as an energy carrier. This important distinction means that energy is usually required to generate hydrogen, and this energy must then be liberated at a later stage when required. In this context, hydrogen has more in common with electricity. In fact, hydrogen combines some of the advantages of fossil fuels (i.e. being a stable physical substance with high energy density) with some of the advantages of electricity (e.g. renewably sourced, clean at point of use, low emissions). The hydrogen economy may seem like a futuristic concept today, but it was first hinted at over 350  years ago, when Robert Boyle produced a combustible gas by reacting acids with iron. This gas was named “hydrogen” by Antoine Laviosier in 1783. The “Voltaic Pile” was developed in

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1799, and this early battery used electrochemistry to generate a stable voltage for the first time. Within a year, Nicholson and Carlisle used this battery to decompose water into hydrogen and oxygen via electrolysis. The world’s first internal combustion engine (the De Rivas Engine) was powered by hydrogen in 1804. In 1874, Jules Verne explicitly explored the idea of a hydrogen society in his novel L’Isle Mysterious, imagining that hydrogen generated from electricity would replace coal as the main fuel for humanity. Hydrogen airships were developed in the mid-nineteenth century, becoming commonplace by the 1930s and travelling all over the world until the Hindenburg disaster struck a serious blow to the first hydrogen era. These innovations were the beginning of the hydrogen economy. The term “hydrogen economy” refers loosely to the comprehensive replacement of fossil fuels with hydrogen as a fuel for heating, mobility, energy storage, and industry. The overall concept was recently summarized by the National Renewable Energy Laboratory, as shown in Fig.  1.2. In this vision, renewable energy from wind, photovoltaics, concentrated solar, and nuclear power will be fed into the grid to provide electrical power, like

Fig. 1.2  Schematic representation of the hydrogen economy. © National Renewable Energy Laboratory

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today. At times when energy supply exceeds demand, excess electricity is converted to hydrogen via water electrolysis. This hydrogen can then be used directly in the existing natural gas pipeline infrastructure, in fuel cell electric vehicles (FCEVs), and other industrial applications. Indeed, hydrogen-based technologies promise novel solutions for sectors as diverse as central heating, mobility and transport, or electricity production (IEA, 2019a; van de Graaf et al., 2020; Upham et al., 2020; Scott & Powells, 2020; IRENA, 2018; Staffell et al., 2019). After having been marginalized for decades as a niche technology (Jones, 1970) and seen as a promising but not yet commercially viable option, a dramatic shift in perspective has taken place in the past decade. Governments around the world have developed national research and innovation policies supporting the uptake of hydrogen technologies and to help their industries to gain a competitive edge in the growing sector. Hydrogen is often seen as a complementary technology that in tandem with renewables has the potential to decarbonize sectors in which alternatives to fossil fuels are still rare, such as long-distance transport or the steel and chemical industries. However, the research and development roadmaps of governments and the importance of hydrogen in overall national energy policies vary considerably (GJETC, 2020; IEA, 2019a; Kosturjak et al., 2019). An early adopter and global front runner in hydrogen technology development is Japan, which places considerable effort in these technologies. After the country lost almost all of its nuclear electricity generation capacity in the wake of the 2011 Fukushima Daiichi nuclear disaster, hydrogen is increasingly regarded as a new way to decarbonize the country and to enhance energy security (Trencher & van der Heijden, 2019). This view is expressed in a future vision, in which green hydrogen will eventually power almost all spheres of economic and social activity, such as mobility through fuel cell vehicles (FCVs) or heating with hydrogen-­ blended gas (METI, 2019). China is set to become another world leader in the development of hydrogen technologies. The government included fuel cells as a strategic emerging sector in its 13th Five-Year Plan (2016–2020) (IEA, 2019b), which means that considerable official and private sector resources were channelled into hydrogen research and development in the recent years, and very likely to continue during the following 14th Five-Year Plan period (2021–2025). China used the same strategy with renewable energy technologies ten years earlier and has become a world leader in this area.

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Governments of other countries like South Korea, Germany, France, and the UK also followed suit recently with ambitious announcements to strengthen their domestic hydrogen research and development capacity and infrastructure (Kosturjak et al., 2019). Even only considering already available technologies, there is no doubt that renewables energy combined with the energy storage and conversion systems like Li-ion batteries, hydrogen, and fuel cells could help steer society towards a sustainable future.

1.5   Fuel Cells Fuel cells are based on the same electrochemical principles as batteries. In a battery, all of the components and chemicals are self-contained. Once the chemicals are used up, the electricity flow stops and the battery is discarded, or recharged. However, fuel can be supplied indefinitely from outside a fuel cell. This allows fuel cells to run continuously and indefinitely, without the need for recharging. Other advantages of fuel cells include extremely high efficiency, and silent operation. A key technology for converting hydrogen to electricity is the polymer electrolyte fuel cell (PEFC). These operate at relatively low temperature (around 90 °C) and as the name suggests are based around a central polymer film. Meanwhile, solid oxide fuel cells (SOFCs) operate at much higher temperature, in the region of 500–900 °C. The solid oxide part of the name references the fact that SOFCs are based around ceramic layers. SOFCs are “fuel flexible”, which means they can consume hydrocarbon-­ based fuels such as methane, methanol, or ethanol in addition to hydrogen. As such they have the advantage of being compatible with our current hydrocarbon-based infrastructure, but also with a future hydrogen-based economy as the price of hydrogen decreases and the availability increases. As the main focus of this book, the science, history, development, and applications of fuel cells are discussed in more detail in Chaps. 3 and 4.

1.6   Critical Raw Materials in Fuel Cells As discussed above, many technologies for sustainable development rely heavily on CRMs, and fuel cells are no different. In PEFCs, the main culprit is platinum. This is utilized as a catalyst for the electrochemical reactions that occur within the electrodes of the fuel cell. Moreover, these platinum electrodes are predicted to contribute almost half of the cost of

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a PEFC “stack” when the technology is scaled up. Because SOFCs operate as much high temperatures compared to PEFCs, platinum is not necessary for efficient operation. Unfortunately, a number of CRMs are still required for SOFCs. These can include strontium, cobalt, yttrium, and a number of rare earth elements, although the exact elements and the quantities required depend on the cell design. These themes will be discussed in more detail in the coming chapters.

1.7   Governance of CRMs The recent shift to renewable energy has been facilitated by ambitious policy goals and sustained by a broad coalition of societal actors in government, industry, and academia. But the rapid development and deployment of these technologies has raised new issues around the governance of CRMs. At present, it could be argued that this sociotechnical shift is unor under-governed (Bleicher & Pehlken, 2020); in particular regarding raw materials required (Lee et al., 2020; Shao & Zhang, 2020; Hodgkinson & Smith, 2018; Sovacool et al., 2020a). It is well established that the early phases of research and development can create new path dependencies (Collingridge, 1980). However, anticipating problems and acting via governance approaches is a relatively new phenomenon. Once a specific sociotechnical pathway is chosen, will we face CRM supply shortages due to resource depletion or geopolitical conflicts in the future? Will public perception shift and new social movements emerge to threaten such pathways? The study undertaken in this book starts with two fundamental assumptions. The first is that prudent governance of clean energy technologies must address the CRM-energy nexus during the early stages of technology development. The second assumption is that the practice of early phase governance should broaden its perspective to include input from different academic disciplines and societal stakeholders. This is important to avoid becoming trapped in future socio-economic path dependencies, which may intensify societal controversies around new technologies (IEA, 2019a). Despite that, most anticipative governance literature focuses on the reduction of potentially high risks rather than broader issues.

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1.8   Structure of This Book Against this background, this book aims to explore how the nexus between sustainable energy, fuel cell technologies, and CRMs could be governed in a more anticipative way that aids the capacity to act once CRM issues emerge in basic fuel cell research. The remainder of this book is structured as follows. Chapter 2 introduces the importance and criticality of CRMs, explores how they are currently governed in the clean energy sector, and highlights potential shortcomings in current approaches to CRMs in mature sustainable energy technologies. Chapters 3 and 4 will introduce the technological background of PEFCs and SOFCs, aimed at non-specialists. Using real-world case studies, the chapters also explore how CRMs are currently utilized in fuel cells, analyse the amounts of CRMs that would be required to fulfil potential energy transitions in certain energy sectors, and discuss potential CRM avoidance strategies in next-generation fuel cell technologies. Chapter 5 will be an introduction to the concepts of technology governance, exploring the themes of an anticipative governance approach in research and innovation, and building on a guiding analytical framework for the governance of CRM use in fuel cells. Chapter 6 describes fuel cell research and development as a spectrum, ranging from fundamentals research, to large system-level pilot projects and wide-reaching economic analysis. It integrates the spectrum with a governance approach based on foresight, engagement, and integration, and discusses tools that can help improve CRM governance in research and development. Chapter 7 will synthesize the findings of the previous chapters and suggest concrete governance tools for early stage intervention in fuel cell research and development, in order to avoid the CRM-related pitfalls experienced by more mature sustainable technologies. These tools will focus on the need for interdisciplinary collaboration.

References Bleicher, A., & Pehlken, A. (Hg.). (2020). The material basis of energy transitions (1st ed.). Academic Press. Blomgren, G.  E. (2017). The development and future of lithium ion batteries. Journal of the Electrochemical Society, 164(1), A5019–A5025. https://doi. org/10.1149/2.0251701jes

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Choi, C. H., Eun, J., Cao, J., Lee, S., & Zhao, F. (2018). Global strategic level supply planning of materials critical to clean energy technologies—A case study on indium. Energy, 147, 950–964. https://doi.org/10.1016/j. energy.2018.01.063 Collingridge, D. (1980). The social control of technology. St. Martin’s Press. David, M. (2018). Exnovation as a necessary factor in successful energy transitions. In The Oxford handbook of energy and society (pp.  519–538). Oxford University Press. Davidson, D.  J. (2019). Exnovating for a renewable energy transition. Nature Energy, 4(4), 254–256. https://doi.org/10.1038/s41560-­019-­0369-­3 Ferro, P., & Bonollo, F. (2019). Materials selection in a critical raw materials perspective. Materials & Design, 177, 107848. https://doi.org/10.1016/j. matdes.2019.107848 GCGET. (2019). A new world. The geopolitics of the energy transformation. Global Commission on the Geopolitics of Energy Transformation, IRENA. GJETC. (2020). Clean hydrogen: Important aspects of production, international cooperation, and certification. German-Japanese Energy Transition Council. Online verfügbar unter http://www.gjetc.org/wp-­content/uploads/2020/ 07/GJETC_Hydrogen-­Society-­Study-­II.pdf Hodgkinson, J. H., & Smith, M. H. (2018). Climate change and sustainability as drivers for the next mining and metals boom: The need for climate-smart mining and recycling. Resources Policy. https://doi.org/10.1016/j.resourpol. 2018.05.016 IEA. (2017). Smart meters installations are quickly accelerating. International Energy Agency. Online verfügbar unter https://www.iea.org/newsroom/energysnapshots/global-­contracted-­installations-­of-­electricity-­smart-­meters.html IEA. (2019a). Perspectives for the clean energy transition—Analysis—IEA. International Energy Agency. Online verfügbar unter. zuletzt geprüft am February 2, 2021, from https://www.iea.org/reports/the-critical-role-of-buildings IEA. (2019b). The future of Hydrogen. Seizing today’s opportunities. Report prepared by the IEA for the G20, Japan. International Energy Agency. Online verfügbar unter https://www.iea.org/reports/the-­future-­of-­hydrogen IRENA. (2018). Hydrogen from renewable power: Technology outlook for the energy transition. International Renewable Energy Agency. Online verfügbar unter https://irena.org/publications/2018/Sep/Hydrogen-­from-­renewable-­power IRENA. (2020a, March). Renewable capacity statistics 2020. Report. International Renewable Energy Agency. Online verfügbar unter https://www.irena.org/ publications/2020/Mar/Renewable-­Capacity-­Statistics-­2020 IRENA. (2020b, June). Renewable power generation costs in 2019. Report. International Renewable Energy Agency. Online verfügbar unter https:// www.irena.org/publications/2020/Jun/Renewable-­Power-­Costs-­in-­2019 Jones, L. W. (1970). Toward a liquid hydrogen fuel economy. University of Michigan Environmental Action for Survival Teach, University of Michigan.

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Kosturjak, A., Dey, T., Young, M., & Whetton, S. (2019). Advancing Hydrogen: Learning from 19 plans to advance hydrogen from across the globe. Future Fuels CRC, University of Adelaide. Online verfügbar unter https://www.adelaide. edu.au/global-­food/system/files/media/documents/2019-­07/RP1.1-­03%20 Hydrogen%20Strategies%20-­%20Final%20Report%20EXTERNAL.pdf Lee, J., Bazilian, M., Sovacool, B., Hund, K., Jowitt, S. M., Nguyen, T. P., et al. (2020). Reviewing the material and metal security of low-carbon energy transitions. Renewable and Sustainable Energy Reviews, 124, 109789. https://doi. org/10.1016/j.rser.2020.109789 METI. (2019, March 12). The strategic road map for hydrogen and fuel cells: Industry-academia-government action plan to realize a “Hydrogen Society”. Ministry of Economy, Trade and Industry. Online verfügbar unter https:// www.meti.go.jp/english/press/2019/pdf/0312_002b.pdf Morton, A. (2020). Victoria plans 300MW Tesla battery to help stabilise grid as renewables increase. The Guardian. Online verfügbar unter. zuletzt geprüft am February 1, 2021, from https://www.theguardian.com/australia-­news/2020/ nov/05/victoria-­p lans-­3 00mw-­t esla-­b atter y-­t o-­h elp-­s tabilise-­g rid­as-­renewables-­increase Pérez-Díaz, J. I., Chazarra, M., García-González, J., Cavazzini, G., & Stoppato, A. (2015). Trends and challenges in the operation of pumped-storage hydropower plants. Renewable and Sustainable Energy Reviews, 44, 767–784. https://doi.org/10.1016/j.rser.2015.01.029 Raman, S. (2013). Fossilizing Renewable Energies. Science as Culture, 22(2), 172–180. https://doi.org/10.1080/09505431.2013.786998 Rehman, S., Al-Hadhrami, L. M., & Alam, M. M. (2015). Pumped hydro energy storage system: A technological review. Renewable and Sustainable Energy Reviews, 44, 586–598. https://doi.org/10.1016/j.rser.2014.12.040 Ruhnau, O., Bannik, S., Otten, S., Praktiknjo, A., & Robinius, M. (2019). Direct or indirect electrification? A review of heat generation and road transport decarbonisation scenarios for Germany 2050. Energy, 166, 989–999. https:// doi.org/10.1016/j.energy.2018.10.114 Scott, M., & Powells, G. (2020). Towards a new social science research agenda for hydrogen transitions: Social practices, energy justice, and place attachment. Energy Research & Social Science, 61, 101346. https://doi.org/10.1016/j. erss.2019.101346 Shao, L., & Zhang, H. (2020). The impact of oil price on the clean energy metal prices: A multi-scale perspective. Resources Policy, 68, 101730. https://doi. org/10.1016/j.resourpol.2020.101730 Sovacool, B., Hess, D. J., Amir, S., Geels, F. W., Hirsh, L. R. M., Miller, C., & Silvast, A. (2020a). Sociotechnical agendas: reviewing future directions for energy and climate research. Energy Research and Social Science. Sovacool, B.  K. (2016). How long will it take? Conceptualizing the temporal dynamics of energy transitions. Energy Research & Social Science, 13, 202–215. https://doi.org/10.1016/j.erss.2015.12.020

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Sovacool, B.  K., Ali, S.  H., Bazilian, M., Radley, B., Nemery, B., Okatz, J., & Mulvaney, D. (2020b). Sustainable minerals and metals for a low-carbon future. Science (New York, N.Y.), 367(6473), 30–33. https://doi. org/10.1126/science.aaz6003 Staffell, I., Scamman, D., Velazquez, A., Anthony, Balcombe, P., Dodds, P.  E., Ekins, P., et al. (2019). The role of hydrogen and fuel cells in the global energy system. Energy & Environmental Science, 12(2), 463–491. https://doi. org/10.1039/C8EE01157E Suberu, Y., Mohammed, Mustafa, W., Mohd, & Bashir, N. (2014). Energy storage systems for renewable energy power sector integration and mitigation of intermittency. Renewable and Sustainable Energy Reviews, 35, 499–514. https://doi.org/10.1016/j.rser.2014.04.009 Trencher, G., & van der Heijden, J. (2019). Contradictory but also complementary: National and local imaginaries in Japan and Fukushima around transitions to hydrogen and renewables. Energy Research & Social Science, 49, 209–218. https://doi.org/10.1016/j.erss.2018.10.019 Uddin, K., Gough, R., Radcliffe, J., Marco, J., & Jennings, P. (2017). Techno-­ economic analysis of the viability of residential photovoltaic systems using lithium-­ ion batteries for energy storage in the United Kingdom. Applied Energy, 206, 12–21. https://doi.org/10.1016/j.apenergy.2017.08.170 UN. (2015, October 21). Transforming our world: The 2030 Agenda for Sustainable Development. A/RES/70/1. United Nations General Assembly. Online verfügbar unter https://sustainabledevelopment.un.org/post2015/ transformingourworld UNFCCC. (2015). Paris agreement. FCCC/CP/2015/L.9/Rev1. Online verfügbar unter http://unfccc.int/resource/docs/2015/cop21/eng/l09r01.pdf Upham, P., Bögel, P., Dütschke, E., Burghard, U., Oltra, C., Sala, R., et al. (2020). The revolution is conditional? The conditionality of hydrogen fuel cell ­expectations in five European countries. Energy Research & Social Science, 70, 101722. https://doi.org/10.1016/j.erss.2020.101722 van de Graaf, T., Overland, I., Scholten, D., & Westphal, K. (2020). The new oil? The geopolitics and international governance of hydrogen. Energy Research & Social Science, 70, 101667. https://doi.org/10.1016/j.erss.2020.101667 Vazquez-Brust, D., Piao, R. S., de Melo, M. F. S., Yaryd, R. T., & Carvalho, M. (2020). The governance of collaboration for sustainable development: Exploring the “black box”. Journal of Cleaner Production, 256, 120260. https://doi.org/10.1016/J.JCLEPRO.2020.120260 Yazami, R., & Reynier, Y. (2002). Mechanism of self-discharge in graphite–lithium anode. Electrochimica Acta, 47(8), 1217–1223. https://doi.org/10.1016/ S0013-­4686(01)00827-­1

CHAPTER 2

Critical Raw Materials

2.1   Defining CRMs Sustainable development relies on the manufacture and roll-out of new energy efficient and carbon-neutral technologies. In simple terms, this translates to factories making products such as wind turbine components, photovoltaic panels, and lithium-ion batteries. Making products requires raw materials, which are substances used in the primary production or manufacturing of goods. Some of these raw materials are readily available, such as iron for producing steel, sand, and limestone for the manufacture of glass, and oil for the production of polymers and plastics. However, sourcing other raw materials can be problematic for a variety of different reasons that we will look into below. When the security of raw material supply chains becomes a risk, certain substances are reclassed as “critical raw materials” (CRMs). The secure supply of CRMs is a long-standing issue. They are at the heart of sustainable development across the globe and drive the Materials Economy as a whole. In September 2020, the European Commission released the “Action Plan on Critical Raw Materials”, the “2020 List of Critical Raw Materials”, and a foresight study on CRMs for strategic technologies and sectors from the perspectives of 2030 and 2050. These highlighted the increasing importance of this complex topic. In this chapter, we introduce the concept of CRMs, their importance in meeting

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sustainable development goals, as well as specific examples of their use in renewable energy technologies. Materials can be classed as CRMs if they are “economically and strategically important to the economy” and/or key industries, but there is “a high-risk associated with their supply” (Ferro & Bonollo, 2019, S. 1). Specifically, CRMs are a selection of so-called rare earth elements, precious metals, and some high demand minerals. One of the first published mentions of CRMs in context was by Professor Raymond Ewell in 1970, in remarks to US Congress about the Soviet Union: “Asia, although the largest continent, is least important to the United States as a source of critical raw materials. Also, it is far away. The United States could get along without Asia altogether, if we had unrestricted access to raw materials from Canada” (Ewell, 1970). Whilst probably accurate at the time this comment seems rather dated today, as Asia has become one of the most important players in CRM supply chains. Soon later, Toyota directly mentioned CRMs in the technological context of redesigning their Toyota Crown passenger car series: “A systematic effort has been made during the designing stage to reduce the unnecessary or wasteful use of critical raw materials. For this reason, the number of models has been reduced” (Toyota Motor Corporation, 1974). Early usage and definitions of CRMs were quite loose, and it wasn’t until much later that attempts to clearly define CRMs arose. For example the European Union (EU) defined CRMs in 2011 as follows: “[T]he European Commission has created a list of critical raw materials (CRMs) for the EU, which is subject to a regular review and update. CRMs combine raw materials of high importance to the EU economy and of high risk associated with their supply” (EU Commission, 2020c). Meanwhile, more recently, Overland describes the concept as a broad term for raw materials with “no viable substitutes” which must be imported by most consumer countries, and whose “supply is dominated by one or a few producers” (Overland, 2019, S. 36–37). It is worth noting that the systematic discussion of CRMs has increased in recent years specifically because of strategic geopolitical concerns over supply chains (e.g. Overland, 2019). Resource extraction and rules of trade affect the import of mineral products which are subject to state regulation, so most envisioned strategies to combat CRM supply issues are at the disposal of governments and national industries with specific governance options at the regulator level (Angerer et al., 2016, S. 140; acatech, 2017, S. 24).

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An increasing recognition of the potential disruptive impacts of material “bottlenecks” in countries with resource-dependent industries has led to the development of many national CRM strategies, including the compilation of lists of CRMs for which there are only very few, if any, substitutes. Arguably the two most influential lists are the ones published by the European Commission (most recently in September 2020) (EU Commission, 2020c) and the U.S. Department of Interior (most recently in May 2018) (DOI, 2018). Both are updated at regular intervals, reflecting the constant changes of geopolitical and sociotechnical influence factors on CRM supply. Another relevant list is compiled by the OECD (Organisation for Economic Co-operation and Development) to provide guidance to all its member states (OECD, 2015). Other strategies at the disposal of governments and national industries are the support for basic research on alternative materials or subsidies for clean energy technologies that are not as dependent on CRMs, as well as increased efforts to improve domestic recycling rates (Hodgkinson & Smith, 2018). The EU “2020 List of Critical Raw Materials” is reviewed every three years, and previous versions were published in 2011, 2014, and 2017. The year-on-year changes between the first three versions are summarized in the periodic table shown in Fig. 1.1. Modifications to these lists are made in order to reflect the ever-changing industrial, geopolitical, and economic landscape. In 2020, 83 different materials were screened for inclusion, and a total of 30 CRMs were selected. Newly included raw materials for 2020 were bauxite, lithium, titanium, and strontium (Table 2.1). Of these, lithium, whilst relatively abundant in the earth’s crust, was selected for the Table 2.1  Critical raw materials 2020 (new as compared to 2017 in bold) Antimony Baryte Beryllium Bismuth Borate Cobalt Coking Coal Fluorspar Gallium Germanium

Hafnium Heavy Rare Earth Elements Light Rare Earth Elements Indium Magnesium Natural Graphite Natural Rubber Niobium Platinum Group Metals Phosphate rock

Phosphorus Scandium Silicon metal Tantalum Tungsten Vanadium Bauxite Lithium Titanium Strontium

Source: The EU 2020 List of Critical Raw Materials (EU Commission, 2020d, p. 3)

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first time due to the rapid rise of battery electric vehicles (BEVs) in recent years. This emphasized the effect that development of new technologies can directly influence the perceived “criticality” of a given element. The list is a tool designed to support EU policy development, to identify areas which require additional investment. In terms of research and development, the list can help inform the direction of the EU’s Horizon 2020, Horizon Europe, and national funding programmes, with particular focus on the CRM-related fields of new mining technologies, CRM substitution, and CRM recovery/recycling.

2.2   CRMs in Sustainable Energy Technologies As discussed in Chap. 1, sustainable technologies are urgently required for decarbonization of the global economy. This requires a huge increase in the scale of manufacture. However, there is a growing awareness that supposedly “green” renewable energy technologies can struggle with a new kind of “fossilization” (Raman, 2013). Perhaps they are not as sustainable as we would like to think. All of these technologies require significant amounts of CRMs in their manufacture. For example the strong magnets used for generating power in wind turbines require significant quantities of CRMs such as neodymium and praseodymium, dysprosium, niobium, borates, and cobalt. Wind power forms an important component of future clean energy production for a number of EU states; however, according to the EU Foresight Study of 2020, only around 1% of the required CRMs are currently mined in the region (EU Commission, 2020e, S. 11). Similarly, large amounts of cobalt (Co) and lithium (Li) are required in Li-ion battery technology. This must be addressed in order to prevent bottlenecks in the roll-out of sustainable technologies that would potentially curtail decarbonization agendas around the world (World Bank, 2020; Lee et  al., 2020). This would include the EU Commission’s 2020 Green Deal, which depends on the rapid extension of renewable energy capacity and low-carbon transport solutions (EU Commission, 2019). The published lists of CRMs are reactive rather than predictive and are not designed to anticipate future trends. Therefore, in its 2020 Foresight Study on Critical Raw Materials for Strategic Technologies and Sectors in the EU, the European Commission projects that CRM supplies will need to increase to meet growing demand for CRM-intense technologies. The study focused on nine technologies in the strategic sectors of renewable

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energy, electric mobility, and defence/aerospace, including phones, laptops, batteries, wind turbines, permanent magnets, photovoltaics, robotics, drones, 3D printing, and electronics in general (Fig.  2.1). In the renewable energy and mobility sectors of relevance to this book, the technologies of focus were lithium-ion batteries, fuel cells, wind energy, electric traction motors, and photovoltaics (Fig. 2.2). Bottleneck analysis was performed to identify potential risks to CRM supply chains. The Foresight Study came up with a series of EU-specific recommendations based on their analyses, including development of manufacturing opportunities, increased raw material production and processing capacity, maintaining leadership in value chains, and overall increased investment. In 2020, Vice-President for Interinstitutional Relations and Foresight at the European Commission, Maroš Šefčovič, highlighted the relationship between CRMs and sustainable development: A secure and sustainable supply of raw materials is a prerequisite for a resilient economy. For e-car batteries and energy storage alone, Europe will for instance need up to 18 times more lithium by 2030 and up to 60 times more by 2050. As our foresight shows, we cannot allow to replace current reliance on fossil fuels

Fig. 2.1  Illustration of the current supply risks of selected raw materials for nine key technologies in three different sectors. (Source: EU Commision, 2020e, S. 10)

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Fig. 2.2  List of CRMs associated with sustainable technologies. (Adapted from EU Commission (2020e)) with dependency on critical raw materials. This has been magnified by the coronavirus disruptions in our strategic value chains. We will therefore build a strong alliance to collectively shift from high dependency to diversified, sustainable and socially-responsible sourcing, circularity and innovation. (EU Commission, 2020b)

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To shed more light on those complex interlinkages, many studies have been published aiming to determine the criticality of materials for advanced energy technology sectors such as transportation and mobility (Hache et  al., 2019; Ortego et  al., 2020; Teubler et  al., 2018; Ballinger et  al., 2020; Valero et  al., 2018), low-carbon electricity generation (Blagoeva et  al., 2016; Boubault & Maïzi, 2019; Gonzalez et  al., 2018; Li et  al., 2020; Rabe et al., 2017), smart cities (David & Koch, 2019), or batteries (Wentker et al., 2019; Weimer & Braun, 2019; Naumanen et al., 2019). These studies originate from different disciplinary backgrounds and apply a broad variety of analytical approaches, but all aimed to identify the material barriers to the future expansion of production capacities and markets, which in turn also determine the strategic value of certain raw materials for national industries. This means that supply risks manifest in different ways how actors approach the governance of raw materials.

2.3   Case Study: Cobalt in Lithium-Ion Batteries Li-ion batteries contain significant amounts of cobalt, as mentioned above, which is an important CRM. Taking BEVs as a case study, the Tesla Model 3 BEV for example reportedly contains ~4.5 kg of cobalt (the Model S released in 2012 contained 11  kg of cobalt per vehicle) (Jolly, 2020). Currently there are around 5 million BEVs in operation around the world (Fig.  2.3; Wagner, 2020b), translating to over 18,000 metric tons of cobalt. Meanwhile, many national or regional governments and even vehicle manufacturers are already planning the phase out of diesel- and petrol-­ powered vehicles in the next few decades in order to meet their obligations in the Paris Agreement. For example the United Kingdom recently announced that all new cars and vans will be fully zero emission at the tailpipe from 2035 (Sharma & Shapps, 2020). In 2019, 92 million motor vehicles were produced worldwide (Wagner, 2020a), and if all of these were replaced with BEVs, the amount of required cobalt would scale to over 414,000 metric tons. Taking this assumption even further, the total number of motor vehicles in the world is estimated to be over 1.4 billion. If all of these were eventually replaced with BEVs, the total amount of cobalt required would be more than 6.3 million metric tons. Meanwhile, in 2019 the total amount of cobalt mined worldwide reportedly totalled ~140,000 metric tons (Garside, 2021). Around half of this mined cobalt is already used in Li-ion batteries, and it is clear that a massive and rapid increase in deployment of BEV technology would far

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Fig. 2.3  The number of battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) currently in operation. (Source: IEA (2020))

outstrip the rate of cobalt production. It would take more than 45 years to extract sufficient quantities of cobalt to support the replacement of all motor vehicles with BEVs, using current technologies. Moreover, these numbers do not even take into account other applications of Li-ion batteries such as gigawatt scale projects for grid stabilization which will also require vast reserves of cobalt. In addition, lithium was added to the EU CRM list in 2020, and similar analysis could be performed for approximately 10 kg of lithium contained in a typical BEV. As such, it is patently clear that Li-ion batteries and BEVs are not a cure-all for decarbonization of society via electrification (although they will play a crucial or central role).

2.4   Factors Increasing CRM Supply Risks CRMs are distributed throughout the earth’s crust, and they are generally obtained by mining. However, the distribution of CRMs is not uniform. For example 98% of “rare earth elements” used in the EU are originally

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sourced from China, whilst 71% of platinum is sourced from South Africa (Fig. 2.4). This highly non-uniform distribution with small regions controlling high concentrations of certain CRMs leads to a significant risk to the supply chain. The supply risk of CRMs can vary considerably over time, and also between regions or sectors (Hodgkinson & Smith, 2018). Much of the scholarly literature (e.g. Gholz, 2014; Achzet & Helbig, 2013; Wilson, 2018; de Ridder, 2013; Overland, 2019) and policy-­ relevant sources (EU Commission, 2020a, OECD, 2015, World Bank, 2020) agrees that China is an important factor in CRM supply risk, since 80% of the global supply of rare earth elements is sourced from open pits in Inner Mongolia. According to the literature, this represents a risk not only because of unforeseen shocks, but also because China intends to control illegal and environmentally unregulated mining activities in the Inner Mongolia region. For example since 2011 stronger environmental regulation was introduced to rare earth element mining, and in 2012, 46 out of a total of 113 extracting mines were forced to close (Wübbeke, 2013). Prior to this, the Chinese government announced that they would cut rare earth element exports (Achzet & Helbig, 2013). Soon an international World Trade Organization (WTO) court case followed, where China lost against the USA, the EU, and Japan; and the claimants argued for abuse of market power (World Trade Organization, 2015). The security of CRM supply for manufacturing industries such as clean energy technology deployment and other high-tech sectors has been a major concern in industrial policymaking circles for some time (BMWi, 2010). The CRM supply perspective implies that, due to the volatile nature of global CRM prices on the global resource market, key industrial stakeholders have limited alternatives to short-term decision-making, which counteracts long-term strategic business planning. Various international organizations and administrations such as the World Bank (2020), the OECD (2015), the EU (2020a), the US Department of Energy, and the Federal Ministry of Economic Affairs in Germany closely monitor international CRM markets. The key concern in recent times is that key manufacturing sectors such as high-tech industries (BMWi, 2010) or renewable energy industries (World Bank, 2020) could suffer disruption to the supply chain, and that CRM prices are particularly volatile. This is important because the percentage of GDP attributed to manufacturing in the EU was around 15% between 2008 and 2018 (World Bank, 2021). Much of this activity relies on CRMs, so there is considerable link between the economy and specific materials.

Fig. 2.4  Regional distribution of CRMs. (Source: EU Commission (2020d, p. 4))

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The general picture that emerges is one of concern over the long-term supply security of CRMs for an entire region. EU raw material policy is based on an understanding of a “link to industry” across supply chains that supply various materials to sustain those industry’s “technological progress” to suit the deployment of “clean technologies” (EU Commission, 2020c). Several studies indicate that there is often only limited awareness of the challenges of CRMs in the early phases of sustainable energy technology development in for example higher education institutions or industrial research laboratories or facilities (Krohns et al., 2011; Hallstedt & Isaksson, 2017; Hancock et al., 2018; Davidson et al., 2007; Hallstedt et  al., 2013; Filho et  al., 2019; Schöggl et  al., 2017; Thapa et  al., 2019; Young et  al., 2016; Vazquez-Brust et  al., 2020). Owing to the nature of basic research, the decisions of an individual are generally driven by particular materials properties, or the desire for fundamental knowledge. This is as it should be, but sometimes a greater awareness of the “bigger picture” should be taken into account. Domestic counterstrategies to secure a stable future CRM supply are necessary because mature energy technologies, such as solar photovoltaics or onshore wind turbines, have already successfully penetrated global markets. This has led to path dependencies and economic lock-in effects that are very difficult to overcome once established (Liebowitz & Margolis, 1995; Cecere et al., 2014).

2.5   The EU Action Plan on CRMs In response to the risks highlighted above, the EU has drawn up an action plan on CRMs in order to improve resilience against future shocks and enable strategic autonomy (EU Commission, 2020a). It proposes actions to reduce the dependency of the EU on third countries, to diversify supply, and to improve resource efficiency and circularity, whilst promoting responsible sourcing globally. Ten concrete actions were proposed, many of which could also be applied in different economic regions (EU Commission, 2020a, pp. 1–2). These included: the launch of the European Raw Materials Alliance; sustainable financing criteria for CRM mining and extraction; research and development on waste processing and CRM substitution; investigation of secondary CRM supplies; identifying CRM mining and extraction projects within the EU; developing expertise in mining and extraction; resource exploration; research on reducing the

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environmental impact of CRM extraction and processing; developing strategic international partnerships; and promoting responsible mining practices. It can be seen that there is a heavy focus on the CRM supply side.

2.6   CRMs in Fuel Cell Technologies As discussed in Chap. 1, fuel cells will be a key enabler of the hydrogen economy and decarbonization. However, fuel cells are highly dependent on various materials classified as CRMs. The European Commission have already identified materials such as platinum and cobalt in PEFCs, or strontium and rare earth elements in SOFCs, which could lead to bottlenecks in the future (Fig.  2.5), although we will investigate the CRM dependencies of PEFCs and SOFCs in more detail in Chaps. 3 and 4 of this book. Some 65% of the CRMs involved in fuel cell manufacture originate from Africa and China (EU Commission, 2020e). Most of the world’s platinum is extracted from South Africa, followed by Russia and Zimbabwe, likely originating from a meteorite impact around 200 million years ago (Powell, 2011). Similar to the case for CRMs in general, the European Commission also included an analysis of CRMs specifically in fuel cell technologies in its foresight study. The recommendations include: diversifying the materials supply; improving local manufacturing opportunities; focusing on recycling, reuse, and substitution; promoting research and development relevant to CRMs in fuel cells; and fostering international collaboration and standardization. The technological aspects of fuel cells are described in much more detail in the following two chapters.

Fig. 2.5  Relevant raw materials used in fuel cells. (Source: EU Commission (2020e, S. 25))

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2.7   Future-Proofing Fuel Cells Now is the perfect time to act in order to “future-proof” fuel cells against issues with CRM use, as promised by the title of this book. If path dependencies are allowed to be established relating to the roll-out of fuel cell technologies, this could be a form of self-sabotage for the technology. The longer we wait, the more difficult it will be to change course. As such, an important course of action should be to target early phase research and development. At present, large-scale deployment of fuel cell technologies has not yet taken place. This means that there could still be an opportunity to avoid locking in path dependencies early in the process. Although an increasing number of governments and industries around the world see hydrogen as a potential technological solution to help address climate change and energy security issues, the markets are by and large still in a niche stage and mostly driven by subsidies and pilot projects. Even the most advanced hydrogen technology applications, such as FCEVs or home-use fuel cell cogeneration systems (such as Japan’s Ene-Farm), so far have just a limited market impact in only a few developed economies. On a positive note, this also means that early stage governance interventions in the research and development processes of novel fuel cell innovations are still possible. In the following two chapters of this book we will introduce the technological basics of high- and low-temperature fuel cells and explore their different applications, as well as their material requirements. The chapters will also take a closer look at the current approaches to CRM selection in research and development processes of fuel cell applications in higher education institutions and commercial research laboratories.

References acatech. (2017). Rohstoffe für die Energiewende: Wege zu einer sicheren und nachhaltigen Versorgung. Achzet, B., & Helbig, C. (2013). How to evaluate raw material supply risks—An overview. Resources Policy, 38(4), 435–447. https://doi.org/10.1016/j. resourpol.2013.06.003 Angerer, G., Buchholz, P., Gutzmer, J., Hagelüken, C., Herzig, P., Littke, R., et  al. (2016). Rohstoffe für die Energieversorgung der Zukunft: Geologie— Märkte—Umwelteinflüsse. acatech—Deutsche Akademie der Technikwissenschaften.

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Naumanen, M., Uusitalo, T., Huttunen-Saarivirta, E., & van der Have, R. (2019). Development strategies for heavy duty electric battery vehicles: Comparison between China, EU, Japan and USA. Resources, Conservation and Recycling, 151, 104413. https://doi.org/10.1016/j.resconrec.2019.104413 OECD. (2015). Critical minerals today and in 2030. Online verfügbar unter https://www.oecd-­ilibrary.org/environment/critical-­minerals-­today-­and­in-­2030_5jrtknwm5hr5-­en Ortego, A., Calvo, G., Valero, A., Iglesias-Émbil, M., Valero, A., & Villacampa, M. (2020). Assessment of strategic raw materials in the automobile sector. Resources, Conservation and Recycling, 161, 104968. https://doi. org/10.1016/J.RESCONREC.2020.104968 Overland, I. (2019). The geopolitics of renewable energy: Debunking four emerging myths. Energy Research & Social Science, 49, 36–40. https://doi. org/10.1016/j.erss.2018.10.018 Powell, D. (2011). Earth: Earthly riches may be heaven-sent: Meteorites possibly peppered planet with precious metals. Science News, 180(8), 11. https://doi. org/10.1002/scin.5591800811 Rabe, W., Kostka, G., & Stegen Karen, S. (2017). China’s supply of critical raw materials: Risks for Europe’s solar and wind industries? Energy Policy, 101, 692–699. https://doi.org/10.1016/j.enpol.2016.09.019 Raman, S. (2013). Fossilizing renewable energies. Science as Culture, 22(2), 172–180. https://doi.org/10.1080/09505431.2013.786998 Schöggl, J.-P., Baumgartner, R. J., & Hofer, D. (2017). Improving sustainability performance in early phases of product design: A checklist for sustainable product development tested in the automotive industry. Journal of Cleaner Production, 140, 1602–1617. https://doi.org/10.1016/j.jclepro. 2016.09.195 Sharma, A., & Shapps, G. (2020). Government takes historic step towards net-zero with end of sale of new petrol and diesel cars by 2030. Sales of new petrol and diesel cars to end in the UK by 2030. Hg. v. Government UK. Government UK. London. Online verfügbar unter. zuletzt geprüft am January 29, 2021, from https://www.gov.uk/government/news/government-­takes-­historic-­ step-­t owards-­n et-­z ero-­w ith-­e nd-­o f-­s ale-­o f-­n ew-­p etrol-­a nd-­d iesel-­c ars-­ by-­2030#:~:text=Step%202%20will%20see%20all,will%20be%20defined%20 through%20consultation Teubler, J., Kiefer, S., & Liedtke, C. (2018). Metals for fuels? The raw material shift by energy-efficient transport systems in Europe. Resources, 7(3), 49. https://doi.org/10.3390/resources7030049 Thapa, R. K., Iakovleva, T., & Foss, L. (2019). Responsible research and innovation: A systematic review of the literature and its applications to regional studies. European Planning Studies, 27(12), 2470–2490. https://doi.org/10.108 0/09654313.2019.1625871

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World Trade Organization. (2015). China—Measures related to the exportation of rare earths, tungsten and molybdenum. Hg. v. World Trade Organization. World Trade Organization. Online verfügbar unter. zuletzt geprüft am January 29, 2021, from https://www.wto.org/english/tratop_e/dispu_e/cases_e/ ds431_e.htm Wübbeke, J. (2013). Rare earth elements in China: Policies and narratives of reinventing an industry. Resources Policy, 38(3), 384–394. https://doi. org/10.1016/j.resourpol.2013.05.005 Young, S., Nagpal, S., & Adams, C.  A. (2016). Sustainable procurement in Australian and UK universities. Public Management Review, 18(7), 993–1016. https://doi.org/10.1080/14719037.2015.1051575

CHAPTER 3

Critical Raw Materials in Polymer Electrolyte Fuel Cells

3.1   What is a Polymer Electrolyte Fuel Cell? In this chapter we introduce the operating principles of polymer electrolyte fuel cells (PEFCs), look at the different components and the materials used therein, summarize the history and applications of PEFCs, and highlight the remaining issues for this technology. We look at the platinum as the primary CRM required in PEFCs and explore current research and development strategies to reduce the amount of required platinum. A fuel cell is essentially a battery, operating on the same basic principle as the alkaline or Li-ion batteries already used today to power our mobile phones, children’s toys, laptops, or flashlights. A conventional alkaline battery generates a voltage by means of two different chemical reactions occurring at the respective electrodes. Zinc metal is steadily oxidized at the cathode to form zinc oxide, whilst manganese dioxide at the anode is reduced to form manganese (III) oxide. Once the zinc or manganese oxide is used up, the reaction stops, the voltage is lost, and the whole battery is discarded. As such, zinc could be described as the solid “fuel” of an alkaline battery. Meanwhile, a PEFC operates according to the same basic principle, with two different chemical reactions at the electrodes generating a voltage. However, in the case of the PEFC, the fuel is hydrogen gas instead of zinc. This can be continuously supplied to the PEFC from outside the device for as long as is required. A schematic of a PEFC is shown in Fig. 3.1. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 M. David et al., Future-Proofing Fuel Cells, https://doi.org/10.1007/978-3-030-76806-5_3

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Fig. 3.1  Schematic of a simple polymer electrolyte fuel cell (PEFC)



More specifically, hydrogen supplied to the anode splits into its constituent hydrogen ions and electrons over a catalyst. This process is known as the hydrogen oxidation reaction (Eq. 3.1). The anode is generally made of platinum-decorated carbon black. The platinum acts as a catalyst to speed up the chemical reactions and is in the form of very small particles. These nanoparticles are finely dispersed on a carbon black support in order to maximize the surface area available for the chemical reactions to take place. The role of the carbon black is to conduct electrons away from the platinum reaction site to the external circuit. 2H 2 ( hydrogen ) → 4 H + ( hydrogen ions ) + 4e − ( electrons )

(3.1)

Meanwhile, oxygen gas supplied to the cathode combines with hydrogen ions and electrons from the anode to form water molecules. This process is known as the oxygen reduction reaction (Eq. 3.2). Similar to the anode, the cathode also comprises platinum-decorated carbon black. However, the oxygen reduction reaction proceeds much more slowly than the hydrogen oxidation reaction, so around ten times more platinum catalyst is needed at the cathode. O2 ( oxygen ) + 4 H + ( hydrogen ions ) + 4e − ( electrons ) → 2 H 2O ( water ) (3.2)

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An important component is the gas diffusion electrode made of porous carbon fibre, which aids the supply of hydrogen or oxygen to the platinum catalyst whilst conducting electrons towards or away from the electrodes. Between the anode and cathode is a polymer electrolyte membrane called Nafion, which is related to Teflon. This separates the reactions at the anode and cathode, generating a voltage. This voltage pushes electrons around the external circuit, and pushes hydrogen ions through the membrane, in a process analogous to a ball rolling down a hill due to gravitational potential energy. This voltage can be used in the same way as the voltage generated by a conventional battery. Taken as a whole, the membrane and electrodes are known as the membrane electrode assembly, or a single cell. These can be sandwiched together to from a fuel cell stack. The stack voltage is simply the sum of the voltages of the individual cells. The cells in a stack are separated by bipolar plates, usually made of graphite or steel. These provide electrical connection between the anode and cathode of adjacent cells, prevent hydrogen and oxygen from directly mixing, and distribute these gases through channels. At each end of the fuel cell stack, end plates made of stainless-steel clamp the cells together with bolts and provide inlets and outlets for oxygen and hydrogen. Rubber or Teflon gaskets serve to seal the fuel cell stack and prevent leaks. The main advantage of PEFCs is that they do not emit pollutants such as carbon dioxide or PM2.5, only water. Another advantage is high efficiency—unlike the internal combustion engine, the efficiency of PEFCs is not limited by the Carnot principle. Indeed, the maximum theoretical energy efficiency of a fuel cell is 83%, compared with just 58% for an internal combustion engine (Vielstich, 2010). Another crucial advantage is their high energy density, translating to enhanced long-term operation and/or extended range. Further advantages include silent operation and continuous operation as long as hydrogen is supplied. Overall, PEFCs combine some of the advantages of both internal combustion engines and batteries. This book focuses on materials. The materials used in PEFCs and how they are sourced are extremely important factors in their research and development. For example carbon black is synthesized by spray pyrolysis of crude oil; carbon fibre is fabricated via heat treatment of woven polymer fabrics; Nafion is a fluorinated polymer; and the gaskets are generally made of rubber or Teflon. As such these are all petroleum-derived products. The stainless steel of the bipolar and end plates is also readily available. In the

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context of this book, the platinum catalyst is the most relevant material, being as it is one of the most high-profile CRMs.

3.2   History of PEFCs As briefly discussed earlier, William Grove first publicly reported his experiments on hydrogen fuel cells in 1842. He designed an experiment in which “alternate tubes of oxygen and hydrogen through each of which passes platinum foil so as to dip into separate vessels of water acidulated with sulfuric acid” were assembled (Grove, 1842). Sixty of these cells were linked together to increase the voltage, giving Grove an “unpleasant shock” and decomposing water via electrolysis “so plainly that a continuous stream of fine bubbles ascends from each electrode”. He called this new electrochemical cell a “gas voltaic battery”, and it is often overlooked that fuel cells are essentially batteries in all but name today. Initially, this new concept was more of a scientific curiosity, since conventional electrochemical batteries at the time were convenient and more reliable to use. However, in 1889 Ludwig Mond and Charles Langer radically improved the design, resulting in a practical cell which ran on air and coal gas (a mixture of hydrogen and carbon monoxide) (Mond & Langer, 1890). They replaced the liquid acid electrolyte with an acid-soaked porous earthenware plate (similar to the design of most batteries at the time) and utilized thin, perforated platinum electrodes. In the 1930s, the mantle of fuel cell research was passed to the engineer Francis Thomas Bacon. He refined the technology considerably over several decades. By using modern materials, higher temperature, high pressure, and switching from acid to alkaline electrolyte he was able to switch from platinum to porous nickel catalysts (Bacon, 1960). In 1959 his team finally developed a practical 5 kW fuel cell which was used as an electric arc welding source (Bacon, 1973). Around the same time, the agricultural equipment company Allis-Chalmers modified a tractor to be powered by 1008 hydrogen fuel cells, generating 15 kW (Bacon, 1969). This was the first fuel cell electric vehicle (FCEV). Bacon’s alkaline fuel cell technology was quickly adopted and improved by NASA and General Electric to provide onboard power and drinking water for crewed space missions (Hacker & Grimwood, 2014). After several teething problems, fuel cells completely replaced batteries on the Gemini V spaceflight, on 21 August 1965 (US Congress, 1965). Hydrogen

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fuel cells were thus established as reliable if expensive technology, and still play an important role in spaceflight to the present day. The use of hydrogen fuel cells by NASA was a major boost to fuel cell research and development, and NASA themselves invested heavily. In 1966, General Motors developed the “Electrovan” prototype FCEV (Craig, 1968), which had a range of 150 miles. The 32 kW fuel cell system was installed under the floor, whilst the tanks for storing pressurized or liquid hydrogen and pure oxygen were placed in the rear of the van. Even then it was recognized that FCEVs would eventually be able to provide better range and economy compared with battery electric vehicles (BEVs). Several other early FCEV prototypes were developed in fits and starts, for example the Hybrid Austin A 40 in 1970, which ran on public roads for three years, as well as military vehicles for which fewer details are available (Kordesch, 1971). Nevertheless, it took several decades after these early forays into FCEV prototype development before commercialization was finally achieved. This delay was largely down to the large cost, as well as the complexity and safety of early hydrogen storage systems. At some point the trend switched from alkaline fuel cells to PEFCs, and increasingly practical prototypes were developed throughout the 1990s to the 2000s by the major automobile manufacturing companies.

3.3   Modern Fuel Cell Electric Vehicles (FCEVs) Toyota has been at the forefront of FCEV development for decades. Early prototypes in the 1990s included a model based on the RAV4L V in 1996, and various FCVH models from 2001. The Toyota FCV-R concept car was released in 2013 at the Tokyo Motor Show. The first truly commercially available FCEV for the public to buy and own was the Toyota MIRAI FCEV, released on 15 December 2014. This had a range of 502 km, was powered by 370 individual fuel cells, and had a power output of 114 kW. This first MIRAI model reportedly contained around 30 grammes of platinum (Onstad, 2019). Honda soon followed suit in Japan, with their release of the Honda FCX Clarity on 10 March 2016. This has a range of 480 km, and a power output of 130 kW. In December of 2020, a new MIRAI model was released (Fig. 3.2) with a range of 850 km, and a power output of 134 kW. The new MIRAI model has reportedly reduced the platinum requirement even further to just 10 grammes, which is only

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Fig. 3.2  The newly released Toyota MIRAI FCEV. ©Stephen Lyth, 2021

slightly higher than the amount of platinum used in catalytic convertors of gasoline-powered vehicles today (i.e. 3–7 grams) (Lenson, 2021). Meanwhile, South Korea also has an active FCEV development programme. Hyundai released their first prototype FCEV in 2001, with a range of just 160 km. Over a decade later, in 2013 the fourth generation of this model became the first mass-produced FCEV available for private lease, the Hyundai ix35, or Tucson FCEV. This had a power output of 100 kW and a range of 594 km. In 2018 the Hyundai NEXO was released with a power output of 120  kW, a range of 570  km, and included free hydrogen fuel supply for three years with purchase (Hyundai, 2021). The NEXO reportedly contains 56 grams of platinum compared to 78 grams in the previous Tucson model (Walker, 2020). Indeed, South Korea has aggressive plans to compete with Japan in terms of establishing a hydrogen society, citing FCEV production targets of 35,000 units by 2022 and a third of cars sold domestically to be FCEVs by 2030 (Stangarone, 2020). The development of FCEVs is not limited to sedan-style vehicles. Heavy-duty trucks account for around 70% of carbon dioxide emissions from commercial vehicles in Japan. Therefore, the deployment of hydrogen trucks could potentially have an even greater impact on sustainable development. Toyota started their Project Portal initiative in 2017 retrofitting a truck with two MIRAI fuel cell stacks to achieve a range of around 480 km (Toyota, 2019). Toyota are now developing their newest generation fuel cell electric trucks in collaboration with Hino, and these are

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expected to have a range of around 600 km when they hit the roads in 2022 (Toyota, 2020). Concurrently, relative newcomer Nikola (a nod to the intense rivalry with BEV manufacturer, Tesla) is making fuel cell electric trucks available for lease, with reported ranges up to an impressive 1900 km (Nikola Motor, 2021). In addition, Hyundai has already established a production line, and successfully shipped ten XCIENT fuel cell electric trucks with a range of 400  km (and an output of 350  kW) to Switzerland in July 2020, with an aim to produce 1600  units by 2025 (Yun-gu and Eun-joo, 2020). Public transport and especially fuel cell electric buses have been inextricably linked with FCEV development from the early days. This is partly due to the very high initial investment required for early fuel cell systems, necessitating large-scale public funds. However, the payoff was clear a benefit in terms of high efficiency, lower emissions, reduced noise pollution, and reliability. Fuel cell buses have been trialled since the late 1990s, and today there are already thousands of FCEV buses in operation around the world (mainly located in China) (IEA, 2019). Another exciting area of application for fuel cells in the public sector is in hydrogen-powered trains, a technology known collectively as “hydrail”. The advantages of fuel cell-powered trains include reduced noise and air pollution compared to diesel-powered trains, and avoiding the electrification of the rail network with expensive high voltage cables. The first hydrogen-powered mining locomotive was demonstrated in 2002 by Nuvera Fuel Cells in Canada. This was followed by the demonstration of a hydrail railcar by the East Japan Railway Company in 2006, and Japan has been heavily involved in the development of hydrail since then. Many other systems have been tested in various projects around the world. Recently, the highest profile hydrail project is in Germany, where Alstom Transport started regular services with a fleet of hydrogen-powered iLINT trains in 2018, using hydrogen generated from wind power. In addition to the above examples, there are many ongoing hydrogen fuel cell development projects and commercialized fuel cell systems including hydrogen-powered forklifts, boats, submarines, drones, and planes. It has been a long and sporadic journey over the past 180 years from the invention of the fuel cell in Grove’s laboratory, to the commercial PEFC systems available today all over the world. However, the story is far from over. As yet, PEFCs are not a truly disruptive technology. Despite the growing number of applications, they are still ultimately a niche technology with limited applications. As long as they remain in this state, fuel

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cells will not be able to contribute significantly to the mitigation of CO2 emissions, or the establishment of a global hydrogen economy.

3.4   Comparing PEFCs and Li-Ion Batteries As we found out in the above section, hydrogen fuel cells are finding uses in a wide variety of different applications. The most commercially successful applications to date are in FCEVs and stationary combined heat and power systems. However, even for these applications, the total number of units sold is only in the tens or hundreds of thousands. Meanwhile, perhaps the closest competitors to PEFCs are Li-ion batteries, which are already ubiquitous in modern day society. Are hydrogen fuel cells really the “fool cells” that Tesla Inc. CEO, Elon Musk, dismisses so readily? Is the research and development of fuel cells a wild goose chase? Conversely, will fuel cells supplant Li-ion batteries as the perfect solution to the energy crisis? The reality of the situation is not as cut and dry as many interests make out, and the real benefits and potential drawbacks of fuel cells should be carefully considered. In the case of electrification of the mobility sector, FCEVs will complement BEVs, rather than acting in direct competition. BEVs are a critical technology in the shift towards emissions-free transport, and have provided the necessary justification to bring in legislation to end the production of gasoline and diesel-powered vehicles. They provide zero emissions, high efficiency, very low noise operation, low operational costs, are ideal for city or commuter usage patterns, and the initial cost of setting up infrastructure is low (Fig. 3.3). However, at some point in the future BEVs will seriously struggle to completely replace the internal combustion engine in the majority of applications across the entire globe, due to the requirement of large amounts of CRMs including lithium and cobalt (as seen in Chap. 2). Range anxiety, that is the fear of running out of fuel during a journey, is an important factor for consumers. In addition, for commercial users with fleets of vehicles, extended time spent charging BEVs requires high power capacity, lots of space, and is considered wasted downtime. This is where FCEVs will have an opportunity to supplement BEVs. FCEVs have zero emissions; high efficiency; and low noise operation in common with BEVs. At the same time, there are several key advantages of FCEVs over BEVs. The first is refuelling time—it routinely takes only 3 to 5 minutes to fully refuel a Toyota MIRAI, compared with 6 to 9 hours to fully charge a Tesla Model S using a wall socket. Another advantage is that

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Fig. 3.3  Schematic comparing some of the advantages of FCEVs and BEVs

long-term infrastructure costs for hydrogen refuelling stations are actually projected to be lower than installation of ubiquitous BEV charging stations, essentially because fewer will be needed. Another extremely important benefit of using FCEVs is the weight, which is tied up with the energy storage capacity and driving range. As a case in point, the Li-ion battery in a Tesla Roadster reportedly weighs a whopping 450 kg, translating to an energy storage capacity of 53 kWh and a range of 393 km. In contrast, the total weight of the fuel cell stack and hydrogen storage tanks in the original Toyota MIRAI is just 184 kg, with an energy storage capacity of 167 kWh, both of which lead to a greater range of 502 km (Davies, 2020). Perhaps the most important factor slowing down the commercialization of electric vehicles is cost. Consumers are more likely to purchase a vehicle if it is perceived as good value for money. At present, FCEVs are significantly more expensive than BEVs at point of sale. The new Toyota MIRAI model is available from 7.1 million JPY (Toyota, 2021), compared to 3.3 million JPY for the Nissan Leaf (Nissan, 2010). Increasing the range of either FCEVs or BEVs has an impact on the vehicle cost, due to the required installation of extra energy storage capacity. However there is a key difference in the way this is achieved in each respective case. For BEVs, increased capacity can be achieved by adding more Li-ion batteries. Doubling the energy capacity requires double the number of batteries. However, batteries are very heavy, so extra capacity must be added to account for carrying around this extra weight. Meanwhile, to increase the energy storage capacity of an FCEV, the hydrogen storage capacity must be increased, rather than increasing the number of fuel cells. This crucial difference means that the cost of increasing the range of

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FCEVs scales at a much slower rate than the cost of increasing the range in BEVs. This situation is depicted graphically in Fig. 3.4, which shows the relationship between cost and range for cars, and “semi-trailer trucks” (Cano et al., 2018). When the study was performed in 2017, hydrogen-powered cars were clearly much more expensive than BEVs with equivalent size and range. However, since BEV cost increases more rapidly with range, cost parity was achieved for FCEVs at a range of 850  km. This is the same range as that of the latest Toyota MIRAI FCEV, suggesting that FCEV manufacturers are very much aware of such analysis. Taking into account future projections of improvements in FCEV technology, cost parity is predicted to occur at an even lower range of 550 km in 2040. Meanwhile, for larger “semi trailer trucks” cost parity was already predicted at a range of 380  km in 2017, meaning that heavy-duty FCEVs are already more cost-effective than BEVs today. Moreover, in 2040 this cost parity is projected to occur at approximately 200 km. This translates into the fact that in terms of cost and range, Li-ion batteries are suited to relatively light-duty applications where range is less important (such as bicycles, scooters, and small cars). Meanwhile, bigger is better in the case of PEFCs, which are better suited to heavy-duty or long-range applications (such as forklifts, sports utility vehicles, long haul

Fig. 3.4  Comparison of the relationship between cost and range for FCEVs and BEVs today, and projected costs for 2040 for (a) cars and (b) trucks (Cano et al., 2018)

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trucks, trains, and boats). Essentially, different technologies are better suited to different applications, and this should be taken into account in the context of sustainable development.

3.5   Platinum in PEFCs Despite the commercial release of FCEVs and their diversification into different mobility sectors, they still represent only a tiny proportion of the 1.6  billion vehicles currently on the planet, or the 100  million vehicles manufactured globally every year. Unfortunately, there are many remaining challenges to overcome before FCEVs will be anywhere near as successful as BEVs. The key challenge is still the high cost, preventing FCEVs from competing with the internal combustion engine. The overall cost of an FCEV can be attributed to three different contributions. First is the most obvious cost of the vehicle at point of purchase, that is the capital expenditure, or CAPEX. Next the cost of running the vehicle must be considered, including fuel and maintenance fees, that is the operational expenses, or OPEX. Finally, the whole life cost should be considered, taking into account both of the above, as well as the projected lifetime of the vehicle and recycling at end of life. Why are PEFC systems expensive, and how can this problem be solved? Figure 3.5 below shows a breakdown of the cost of different components in a PEFC stack, projected for different scales of production. For a small production scale of 3000  units per year, the membrane is the biggest

Fig. 3.5  Breakdown of the cost of different components in a fuel cell stack, for production scales of (a) 3000 and (b) 500,000  units per  annum. (Source: data taken from Thompson et al., 2018)

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contributor to stack cost (28%), followed by the electrocatalyst layer (21%). When the production scale is increased to globally relevant levels of 500,000 units per year, by far the biggest contributor to the stack cost is the electrocatalyst layer (45%) (Thompson et  al., 2018). A dramatic increase in the proportional contribution from the electrocatalyst layer is expected. This is because the cost of other components in the stack (i.e. the membrane, gas diffusion later, bipolar plates, etc.) will decrease with economies of scale. However, the electrocatalyst contains platinum, and the procurement of this CRM is almost directly linked to the market price of the element. The cost of purchasing platinum cannot be significantly reduced by purchasing in bulk quantities. As such, as the market share of PEFCs and FCEVs increases, the price of platinum is expected to become the dominant factor in determining the cost of the systems. Earlier in this book, we showed that the amount of cobalt required to replace the majority vehicles using internal combustion engines with BEVs is prohibitive. Here, we perform a similar simplified analysis for conversion of the global motor vehicle fleet to FCEVs. As mentioned earlier, the original Toyota MIRAI model reportedly contained 30  grams of platinum, the current MIRAI model contains around 10 grams of platinum, and the Hyundai NEXO reportedly contains 56 grams of platinum. Heavy-duty vehicles such as trucks, buses, and trains will contain correspondingly larger amounts of platinum. However, for the sake of simplicity we will use 30 grams per vehicle as a representative value. As of 2019 there were an estimated 25,210 FCEVs on the roads, including cars, forklifts, buses, and trucks (IEA, 2019). Using the above assumptions, this translates to at least 756 kg of platinum, not taking into account the larger amounts of this CRM needed for buses, trains, and trucks. If the number of FCEVs on the roads were to match deployment levels currently reached by BEVs (i.e. around 5,000,000 vehicles), this would require at least 150,000  kg of platinum or 150 metric tons. Replacing all 92  million motor vehicles produced annually with FCEVs would correspondingly require 2760 metric tons of platinum. Fully switching all 1.6 billion vehicles in the world to FCEVs would require at least 18,000 metric tons of platinum using current technologies. Indeed, global demand for platinum is forecast to increase to 10.4 metric tons for FCEVs by 2030, or 27 metric tons when taking all PEFC and hydrogen applications into account (Onstad, 2019). According to our analysis, this demand will dramatically increase as FCEVs become more common.

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Unfortunately, these numbers do not tally with the available platinum resources. It is estimated that just 190 metric tons of platinum is extracted annually at present, and that only 10,000 tons of platinum has ever been mined in all of human history (corresponding to a hypothetical cube with sides of just 7.7 m) (Anderson, 2019). Therefore, according to the above analysis, enough platinum is mined to produce around 6.3 million FCEVs per annum, and it would take more than 250 years to replace all of the vehicles in the world at this rate. It is clear that the massive and rapid scale­up of FCEVs would far outstrip platinum production at current levels. This is a serious bottleneck that should be discussed by all players in the fuel cell community. Moreover, these calculations ignore the other myriad and important applications for platinum, such as catalytic convertors, jewellery, chemical production, petroleum refining, and electrical applications. The total amount of unmined reserves should also be considered, and it can’t be guaranteed that the supply of platinum will be constant over the coming decades. A massive increase in platinum utilization in the FCEV industry would also potentially impact the market price of platinum. Whilst platinum is currently the cheapest it has been in over a century relative to gold, if demand exceeds supply then this situation is likely to rapidly change.

3.6   CRM Avoidance in PEFCs Clearly there is a huge and fundamental issue with the current situation regarding platinum in PEFCs. Whilst this technology offers clean power with high efficiency and durability, the necessity for the use of CRMs is its Achilles heel. Luckily, many scientists and engineers are aware of this pertinent issue. Whilst the commercialization of platinum-containing PEFCs continues at pace, concerted efforts are underway in research labs across the world to decrease or completely eliminate the use of platinum. The earliest fuel cells used perforated or porous platinum foils as catalysts. To reduce the amount of platinum required, these foils were later replaced with porous nickel or titanium mesh coated with thin films of platinum. In the modern era, carbon black decorated with highly dispersed platinum nanoparticles is the favoured technology. Each of these steps was associated with a decrease in the amount of required platinum, due to increasing surface area. The chemical reactions within a PEFC occur at the surface of the platinum catalyst. The more accessible surface that is available to the hydrogen or oxygen molecules, the faster the rate of

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the reaction. This can be quantified by a term called the mass activity, which is effectively the current density generated by the fuel cell per unit mass of platinum, measured in amps per gram of platinum (i.e. A gPt−1). Increasing the mass activity reduces the amount of platinum required in PEFCs. Achieving high mass activity is one of the main driving forces in fundamental PEFC catalyst research. This is reflected in the provision of calls and amount of budget provided from funding bodies. For example the Fuel Cells and Hydrogen Joint Undertaking (FCH JU) has played a central role in coordinating fuel cell projects in the European Union under the Seventh Framework Programme for Research and Technological Development (FP7) with a budget of 940  million euro and under the Horizon 2020 programme with a total budget of over 1.33 billion euro. A core objective of the FCH JU is “minimal use of critical raw materials” (FCH, 2021). Similar programmes with similar objectives are coordinated by for example the United States Department of Energy (US DOE) and the Japanese Society for the Promotion of Science (JSPS). After the first step of obtaining research funding, there are several main strategies for increasing the mass activity of PEFC catalysts, and reducing the platinum loading at a research and development level. Details of these approaches are outlined in the sections below. As discussed above, conventional PEFC electrocatalysts today comprise platinum nanoparticles decorated onto a nanostructured carbon black support. A common example of this type of catalyst is TEC10E50E, as developed by Tanaka Kikinzoku Kogyo (TKK) corporation. This has a relatively high loading of 50  wt%, which means that half of the catalyst mass is platinum, and half carbon black. A magnified image of this class of platinum-decorated carbon catalyst is shown below in Fig. 3.6. The platinum nanoparticles are visible as dark spots a diameter of around 2  nm. These are decorated on a proprietary high surface area carbon support which shows up in light grey in this image. A pore can be seen at the bottom of the image, and these empty spaces are important for transporting oxygen or hydrogen to the catalyst surface. This platinum-decorated carbon electrocatalyst is sprayed or printed onto the membrane GDL electrode, before assembly of the PEFC. The catalyst loading at the cathode is generally around ten times higher than that at the anode, because the oxygen reduction reaction is rather sluggish compared to the hydrogen oxidation reaction. For this reason, most research in this field focuses on the cathode reaction. A typical platinum

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Fig. 3.6  (a) Transmission of electron micrograph and (b) schematic of a typical platinum-decorated carbon black catalyst used in PEFC research. (Image courtesy of David Rivera, 2018)

loading used at the cathode for research purposes is 3 grams of platinum per square metre (i.e. 0.3 mgPt cm−2). The US DOE has specific research targets for reducing the amount of platinum and platinum group metal (PGM) loading used in PEFCs. For example the 2020 target was to use less than 1 gram per square metre at the cathode (i.e. 0.1  mg  cm−2). However, in the medium to long term even lower targets such as 0.625 grams per square metre may be required (i.e. 0.0625 mg cm−2) (Kongkanand & Mathias, 2016). Eventually, avoiding the use of PGMs altogether is also desirable. Achieving these targets will be extremely challenging, and many different approaches are being taken to reduce platinum loading. Some of these are outlined below.

3.7   Ultra-Low Platinum Loading One of the most obvious ways to reduce the amount of platinum used in a PEFC is simply to decrease the platinum loading, in other words using less platinum per unit area. In practice, this is usually achieved by distributing the decorated platinum more finely, thereby decreasing the particle size. This can be done by using different nanostructured catalyst supports (such as carbon nanotubes or graphene), although the increased cost of modified or novel carbon materials must also be taken into account. Another alternative is to vary the method used to deposit platinum onto the surface of the carbon support, to gain a high degree of control over

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the nanoparticle size or the thickness of the catalyst layer (O’Hayre et al., 2002). Available methods include chemical precipitation, electrodeposition, colloidal dispersion, sol-gel synthesis, sputtering, or atomic layer deposition. Such techniques can be highly successful in improving the initial mass activity of platinum, as well as PEFC performance, and relatively high power densities have been achieved for loadings down to 32 milligrams of platinum per square metre (i.e. 3.2 μg cm−2), well below the DOE targets mentioned above (Ganesan & Narayanasamy, 2019).

3.8   Platinum Nanoparticle Shape Control Another method of improving the mass activity of platinum in a PEFC is to maximize the catalytic activity, in other words controlling how fast the chemical reactions occur at the surface of platinum. Conventional platinum nanoparticles are roughly spherical (Fig. 3.6). Meanwhile, for a cube of platinum with perfectly aligned crystal structure, the different faces have slightly different patterns of atoms at the surface. Furthermore, these different crystal facets actually have different catalytic activity. The so-called 111 facet is packed hexagonally, like snooker balls in a rack, and this has the highest activity for reducing oxygen (Markovic et al., 1995). Researchers can increase the proportion of these 111 facets in platinum nanoparticles by tweaking the chemistry during growth phase, to produce polyhedral structures with clearly defined crystal lattices at the surface (Wang et al., 2008). Shapes that can be synthesized reproducibility in the lab range from cubes, truncated cubes, cuboctahedra, truncated octahedra, and octahedra. Of these different geometries, platinum octahedra are purely 111 across their whole surface, and therefore should have the highest mass activity. This process can be taken a step further by etching the generated nanoparticles. Depending on the experimental conditions, different facets will etch at different rates, and this can lead to the formation of hollow cage-like structures (Peng & Yang, 2009). These platinum cages contain much less platinum and expose the greatest possible proportion of 111 sites to the surface. As such they can achieve extremely high mass activity.

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3.9   Platinum Alloys Another strategy for increasing the mass activity of platinum is alloying, which simply means mixing platinum with another metal. This can “dilute” the platinum without necessarily sacrificing the catalytic activity. In fact, the catalytic activity of platinum alloyed with different atoms can even have fundamentally higher catalytic activity compared to pure platinum. Examples include nickel (Pt3Ni), cobalt (Pt3Co), iron (Pt3Fe), scandium (Pt3Sc), and titanium (Pt3Ti) alloys (Greeley et al., 2009). This is because the electronic structure is modified by the presence of different atoms, in turn affecting how oxygen binds to the surface. A variation on the theme of alloying is to control the distribution of the different elements within the nanoparticles. In a conventional alloy, the metal atoms are uniformly mixed throughout the particle. Meanwhile, core-shell type nanoparticles are able to increase the mass activity by concentrating platinum at their surface, whilst the interior is filled with for example a non-CRM metal. In fact, alloying is one of the most successful methods to improve mass activity of platinum to date, and it is already used successfully in commercial applications. Pure platinum nanoparticles are no longer the state-of-­ the-art catalyst for FCEVs such as the Toyota MIRAI, which reportedly utilizes Pt3Co nanoparticles (Yoshida & Kojoima, 2015).

3.10   Issues with Decreasing the Platinum Loading In all of the above methods to reduce the amount of platinum required in PEFCs, the mass activity is improved in order to ultimately use less platinum. However, there are a number of important issues with these technologies. Firstly, many of these techniques involve complex processing steps, are slower to complete, difficult to scale, or replace some of the platinum content with other CRMs. This means that the cost benefit of using less platinum may be offset by the increased cost of the different process. Another issue is stability—smaller, polyhedral, or bimetallic nanoparticles are inherently less thermodynamically stable. This means that these complex and tiny architectures do not survive for long in the harsh environment of a fuel cell. They will dissolve and/or agglomerate. Finally, platinum is still the active material in all of the above technologies, and once scaled to industrially relevant levels the same fundamental issues associated with the use of CRMs will remain in some form.

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3.11   Recycling An often-overlooked method of reducing the amount of platinum required for the fuel cell industry as a whole is to ensure that recycling is performed as efficiently and fully as possible at the end of life. Platinum recovery from end-of-life PEFCs is in general an under-researched field. Encouragingly, the leading global provider of PEFCs, Ballard, has a refurbishment programme in which they accept used fuel cells for reconditioning (Howe, 2018). In this process, they take fuel cell stacks which have been used for 5–10 years and replace the “worn” components, bringing the device back up to original specification for a fraction of the cost of purchasing an entirely new system. Meanwhile, they take the degraded electrodes and dissolve out the platinum from the electrocatalyst layers, to recover around 95% of the original material. Thinking about total life-cycle management in this way is an effective and important way to ensure that platinum can be reused indefinitely in multiple generations of PEFCs. However, recycling does not solve the problem of the vast reserves of CRMs required to massively expand the PEFC industry in the first instance.

3.12   Platinum-Free Catalysts In a more extreme effort to avoid the use of CRMs in PEFCs, research into non-PGM catalysts has been underway for several decades. In this case the need for platinum can be completely eliminated. Platinum-free catalysts often take their inspiration from highly efficient catalysts in nature, such as chlorophyll or haemoglobin. To emulate these biological catalysts, mixtures of various carbon, nitrogen, and iron-containing substances are baked at high temperatures, to form so-called Fe-N-C catalysts, resembling soot (Mufundirwa et al., 2020). This class of non-PGM catalyst has the advantage of using cheap and readily available precursors—carbon, nitrogen, and iron are some of the most abundant elements in the universe. To date, state-of-the-art PEFCs using Fe-N-C electrocatalysts can reach around half of the power density of platinum-based PEFCs. Whilst the catalytic activity of non-PGM materials is unlikely to ever match the high activity of platinum, there is a great deal of interest and research funding associated with these materials. For example the US DOE funds a major programme known as the Electrocatalysis Consortium (Electrocat), allocating around US $4  million a year, within the broader Hydrogen and Fuel Cells Program (Zelenay,

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2020). Meanwhile in Europe, CRESCENDO was a 2.7 million euro project focusing on PGM-free electrocatalysis development funded under the prestigious EU Horizon 2020 programme (Hydrogen Europe, 2018). Several prototype fuel cell systems have been developed using these platinum-­free electrocatalysts, including a prototype FCEV developed by Daihatsu (Hyundai, 2013), and a small charging device produced by a Ballard and Nissinbo collaboration (Kishimoto et al., 2016). In addition, a start-up company in the US called Pajarito Powder sells such catalysts commercially (Serov et al., 2019).

3.13   Chapter Conclusion In summary, this chapter introduced the fundamental concept of PEFCs, their advantages, their history, and their modern applications in sustainable development. We compared PEFCs with their closest rival, Li-ion batteries, and looked at how much platinum would be required for their roll-out in mobility applications at a global scale. Finally, we discussed various possible solutions for the avoidance of CRMs in next-generation PEFC technologies.

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Kordesch, K. V. (1971). Hydrogen-air/lead battery hybrid system for vehicle propulsion. Journal of the Electrochemical Society, 118(5), 812. https://doi. org/10.1149/1.2408171 Lenson, B. (2021). How much platinum is in a catalytic converter?—Reclaim, recycle, and sell your precious metal scrap. Reclaim, Recycle, and Sell your Precious Metal Scrap. Online verfügbar unter. zuletzt aktualisiert am January 29, 2021, zuletzt geprüft am January 29, 2021, from https://www.specialtymetals.com/ blog/2018/3/12/how-­much-­platinum-­is-­in-­a-­catalytic-­converter Markovic, N. M., Gasteiger, H. A., & Ross, P. N. (1995). Oxygen reduction on platinum low-index single-crystal surfaces in sulfuric acid solution: Rotating ring-Pt(hkl) disk studies. The Journal of Physical Chemistry, 99(11), 3411–3415. https://doi.org/10.1021/j100011a001 Mond, L., & Langer, C. (1890). V. A new form of gas battery. Proceeding of the Royal Society London, 46(280–285), 296–304. https://doi.org/10.1098/ rspl.1889.0036 Mufundirwa, A., Harrington, G.  F., Ismail, M.  S., Šmid, B., Cunning, B.  V., Shundo, Y., et al. (2020). Gram-scale synthesis of alkoxide-derived nitrogen-­ doped carbon foam as a support for Fe–N–C electrocatalysts. Nanotechnology, 31(22), 225401. Nikola Motor. (2021). Nikola Two. Online verfügbar unter. zuletzt geprüft am January 29, 2021, from https://nikolamotor.com/two Nissan: Nissan Leaf. (2010). Online verfügbar unter. zuletzt geprüft am January 29, 2021, from https://www3.nissan.co.jp/vehicles/new/leaf.htm O’Hayre, R., Lee, S.-J., Cha, S.-W., & Prinz, F. B. (2002). A sharp peak in the performance of sputtered platinum fuel cells at ultra-low platinum loading. Journal of Power Sources, 109(2), 483–493. https://doi.org/10.1016/ S0378-­7753(02)00238-­0 Onstad, E. (2019). Exclusive: Bosch goes for platinum-light fuel cells. https:// www.facebook.com/Reuters. Online verfügbar unter. zuletzt geprüft am January 29, 2021, from https://www.reuters.com/article/us-­platinum-­week­bosch-­fuelcells-­exclusi-­idUSKCN1SJ0FG Peng, Z., & Yang, H. (2009). Designer platinum nanoparticles: Control of shape, composition in alloy, nanostructure and electrocatalytic property. Nano Today, 4(2), 143–164. https://doi.org/10.1016/J.NANTOD.2008.10.010 Serov, A., McCool, G., Romero, H., McKinney, S., Lubers, A., Odgaard, M., et al. (2019). PGM-free oxygen reduction reaction electrocatalyst: From the design to manufacturing. Meeting Abstracts. https://doi.org/10.1149/ ma2019-­01/30/1487 Stangarone, T. (2020). South Korean efforts to transition to a hydrogen economy. Clean Technologies and Environmental Policy, 1–8. https://doi.org/10.1007/ s10098-­020-­01936-­6

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Thompson, S. T., James, B. D., Huya-Kouadio, J. M., Houchins, C., DeSantis, D. A., Ahluwalia, R., et al. (2018). Direct hydrogen fuel cell electric vehicle cost analysis: System and high-volume manufacturing description, validation, and outlook. Journal of Power Sources, 399, 304–313. https://doi. org/10.1016/j.jpowsour.2018.07.100 Toyota. (2019). Toyota Mirai fuel cell stack propels ten zero-emissions trucks— Toyota UK. https://www.facebook.com/toyotauk. Online verfügbar unter. zuletzt geprüft am January 29, 2021, from https://blog.toyota.co.uk/ toyota-­mirais-­hydrogen-­fuel-­cell-­trucks Toyota. (2020). Heavy-duty fuel cell electric truck verification tests to start in spring 2022—Toyota UK media site. Online verfügbar unter. zuletzt geprüft am January 29, 2021, from https://media.toyota.co.uk/2020/10/ heavy-­duty-­fuel-­cell-­electric-­truck-­verification-­tests-­to-­start-­in-­spring-­2022/ Toyota. (2021). Toyota Mirai. Online verfügbar unter. zuletzt geprüft am January 29, 2021, from https://toyota.jp/mirai/ US Congress. (1965). United States aeronautic and space activities. Hg. v. US Congress. Vielstich, W. (2010): Ideal and effective efficiencies of cell reactions and comparison to carnot cycles. In W. Vielstich, A. Lamm, H. A. Gasteiger, & H. Yokokawa (Hg.), Handbook of Fuel Cells. John Wiley & Sons, Ltd. Walker, A. (2020). Guest editorial: Johnson Matthey technology review special edition on clean mobility. Johnson Matthey Technology Review. https://doi. org/10.1595/205651320X15874763002058 Wang, C., Daimon, H., Onodera, T., Koda, T., & Sun, S. (2008). A general approach to the size- and shape-controlled synthesis of platinum nanoparticles and their catalytic reduction of oxygen. Angewandte Chemie, 120(19), 3644–3647. https://doi.org/10.1002/ange.200800073 Yoshida, T., & Kojoima, K. (2015). Toyota MIRAI fuel cell vehicle and progress toward a future hydrogen society. Electrochemical Society Interface, 24, 45. https://doi.org/10.1149/2.F03152if Yun-gu and Eun-joo. (2020). S. Korea’s Hyundai Motor exports first hydrogen trucks to Switzerland. Online verfügbar unter. zuletzt geprüft am January 29, 2021, from https://pulsenews.co.kr/view.php?year=2020&no=691064#:~:te xt=Hyundai%20Motor%20which%20established%20the,Gwangyang%20in%20 South%20Jeolla%20Province Zelenay, P. (2020). ElectroCat (electrocatalysis consortium). Report. Los Alamos Laboratories. Los Alamos (LA-UR-20-24045).

CHAPTER 4

Critical Raw Materials in Solid Oxide Fuel Cells

4.1   History and Overview of Solid Oxide Fuel Cells (SOFCs) 4.1.1  Early Development The development of SOFCs can be traced back to 1897 when Walther Nernst began work on an incandescent light bulb filament made from a mixture of zirconium oxide (ZrO2, referred to as zirconia) and yttrium oxide (Y2O3, referred to as yttria). While insulating at room temperature, this compound would conduct electricity when heated to high temperatures and would produce a brilliant white light. The lamps were successfully marketed for a time, but were quickly superseded by the tungsten filament, however, not before Nernst sold his patents to several companies making him a wealthy man (“The Nernst Lamp in America”, 1901). Nernst correctly described his filament, or “glower” as it was termed, as an oxygen ion conductor, which, as we discuss below, forms the basis for the SOFC. The first patent on fuel cells using such ceramics materials was filled by Haber in 1905, but it was not until 1937 that zirconia-based ceramics were used in a fuel cell by Baur and Preis (Möbius, 1997). Commercial interest in SOFCs did not occur until the 1960s, when a number of US companies filed patents on solid oxide fuel cell technology, partly driven by the need to provide onboard power to spacecraft where expense was of little concern (Möbius, 1997). One of these companies was Westinghouse © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 M. David et al., Future-Proofing Fuel Cells, https://doi.org/10.1007/978-3-030-76806-5_4

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Electric Corporation (which later became Siemens Westinghouse Power Corporation) which was the clear leader in SOFC technology until the 2000s (Behling, 2013). 4.1.2  Operating Principles and Components The basic operating principles of the SOFC are almost identical to the polymer electrolyte fuel cell (PEFC) introduced in the previous chapter, with the crucial differences being that the SOFC is made of solid ceramic and metal components and that it operates at much higher temperatures (500–1000 °C). Ceramics are a family of materials often characterized as crystalline inorganic solids. Some ceramics are made up of a combination of metal atoms and oxygen atoms and are hence called oxides. In these oxides, the metal and oxygen atoms form in a periodic arrangement we refer to as a crystal lattice and say that the material is crystalline. This is shown schematically in Fig. 4.1a. By combining the right oxides, referred to as doping, it is possible to engineer the material such that some of the oxygen is missing from the crystal lattice, as shown in Fig. 4.1b. At high temperatures oxygen can move through the material by hopping into the positions with missing oxygen atoms. This is the basic principle of the oxygen ion conductor, as discovered by Nernst. It can be thought of as

Fig. 4.1  Schematics of a metal oxide crystal lattice. (a) “Perfect” crystal structure. (b) Crystal structure with oxygen deficiency due to the introduction of a dopant, allowing for oxygen ion transport to take place

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similar to the way a material like copper conducts electricity in the form of electrons, but it is the oxygen that is moving instead. An oxygen ion conductor forms the heart of the SOFC, because it allows oxygen to pass but blocks electrons. A schematic of an SOFC is shown in Fig. 4.2. The oxygen ion conductor, or electrolyte, separates two gas atmospheres: one containing a fuel such as hydrogen (H2) or carbon monoxide (CO) and one containing an oxidizing atmosphere such as air or pure oxygen (O2). The other components which make up the SOFC are the cathode, the anode, and the interconnects. 1 At the cathode, oxygen from the gas atmosphere ( O2 ) combines with 2 two electrons (2e−) and enters into a position in the oxide where the oxygen is missing (a vacancy, vO·· ) to become incorporated into the cathode (O2+). This is called the oxygen reduction reaction and is given in Eq. (4.1).



1 O2 + 2e − + vO·· → O 2 + 2 (4.1)

The resultant oxygen from the cathode travels through the electrolyte to reach the anode. Here it reacts with the fuel (H2 or CO) to produce a waste by-product (H2O or CO2), two electrons (2e−), and leaves behind a missing oxygen atom ( vO·· ). These reactions are given in Eqs. (4.2) and (4.3).

H 2 + O 2 + → H 2O + 2e − + vO·· (4.2)



CO + O 2 + → CO2 + 2e − + vO·· (4.3)

Fig. 4.2  Schematic of the operational principles and components of an SOFC

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Note that at the anode the reaction produces electrons, while at the cathode they are consumed. Because the electrolyte is blocking to electrons, as previously discussed, they must flow around an external circuit. If we take a look at the total reaction that is occurring over the SOFC running using either a H2 or CO fuel, we see that, combining Eqs. (4.1) and (4.2) or (4.3), the overall reaction is given by Eq. (4.4) or Eq. (4.5).



1 O2 + H 2 → H 2O 2 1 O2 + CO → CO2 2

(4.4) (4.5)

This is the same reaction that occurs when we combust hydrogen or carbon monoxide, and therefore we know that energy must be released. But rather than be released purely as heat, as when burning the fuel, the energy from the reaction can be extracted via the electrons travelling round the external circuit. In this way we can directly extract the chemical energy of the fuels electrically. Hence, we call fuel cells electrochemical cells. This method is much more efficient than the conventional method of combusting the fuels, using the heat to produce steam from water, then using the steam to drive a turbine, which then drives an electric generator. In typical applications a series of cells will be combined to form a stack. Interconnects are required to connect between neighbouring cells while ensuring each cell is electrically isolated. Usually, the interconnects also include gas channels to supply fuel and oxygen, in the form of air, to the relevant electrodes. While the interconnects do not play a role in the reactions, and may not be considered an active component of the SOFC, they nonetheless are an important consideration when it comes to SOFC development and design. 4.1.3  Advantages and Disadvantages SOFCs share many of the advantages as PEFCs which were discussed in the previous chapter. They have no moving parts, and so operate silently. Unlike conventional batteries they do not have an intrinsic energy capacity and can be run continuously for as long as fuel and oxygen are supplied. Because SOFCs directly convert chemical energy to electrical power they

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are inherently efficient, with theoretical efficiencies exceeding 50% (Ivers-­ Tiffée et al., 2001). Unlike PEFCs, SOFCs run at much higher operational temperature (500–1000 °C), which brings further advantages. Perhaps the most immediate significant advantage is that precious metal catalysts are not required on the electrodes, although as discussed below, other CRMs are still needed. The higher temperatures also allow a much greater degree of fuel flexibility than PEFCs. SOFCs can run on hydrogen, carbon monoxide, as well as other hydrocarbon fuels such as methane or ethanol. In particular, this feature makes SOFCs highly desirable as a transition technology, being compatible with our current gas production and distribution infrastructure, while enabling a smoother switch to emission-free hydrogen as environmentally friendly production and distribution matures. The higher temperatures also enable the use of SOFCs in combined heat and power (CHP) applications, where waste heat from the cells can be utilized (such as heating a home). These applications have an even higher efficiency than direct power application, and can be as high as 90% (Maru et al., 2010), which is unrivalled by any other energy conversion technology. Another benefit of SOFCs is the ability to operate in reverse as either a dedicated solid oxide electrolyser cell (SOEC) or a reversible solid oxide cell (rSOC), albeit with slightly difference material requirements. In this mode of operation electrical power is applied, rather than extracted, and fuel can be produced via electrolysis. Examples of this would be the production of hydrogen or carbon monoxide from water for carbon dioxide, respectively, and are the reverse of the reactions given in by Eqs. (4.4) and (4.5). In this way an SOEC, or an rSOC, could utilize excess electricity produced from renewables to synthesize fuels for storage and/or distribution and then convert them back to electricity using an SOFC or rSOC when required. Many of the advantages of SOFCs are due to the high operation temperature; however, this also brings several disadvantages. The first is long start-up and shut-down times as the cell heats up to or cools down from the operating temperature. This makes SOFCs less suitable to applications with dramatically fluctuating power requirements, such as automobiles operating within a city, unless combined with a system to buffer the output such as a battery or operating as a range extender or auxiliary power unit. Probably the most significant issue with SOFCs, however, is degradation of the cells over long-term operation. At high temperatures,

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differences in the thermal expansion coefficients1 between the components can cause the SOFC to fracture due to the brittle nature of the ceramic materials. The high temperatures can also cause the surface of the electrodes to degrade and different components to react together unfavourably, lowering the power output and efficiency of the cell. Finally, the fabrication of SOFCs requires the components to be sintered2 at high temperature which causes the manufacturing costs to be high.

4.2   Material Choices in SOFCs Compared to PEFCs, the choice of materials available for each component is larger for SOFCs. This is partly due to the wide range of temperatures and variety of fuels that SOFCs are capable of operating under, making particular components more suitable for certain conditions. For the sake of our discussion, it is worth discussing the material requirements for each component and mentioning several of the options available. 4.2.1  Electrolytes Requirements for the electrolyte in SOFCs are that it must be a good oxygen ion conductor, completely blocking to electrons, and fully dense such that gas from the fuel or air atmospheres cannot pass through. Ideally, the electrolyte would be as thin as possible, minimizing the resistance for oxygen ions to pass across the membrane; however, the ability to manufacture thin electrolyte layers which are robust and form a gas tight membrane typically limit this to approximately 10μm. There are four families of materials that are the primary candidates for electrolytes in SOFCs: zirconia-­ based electrolytes, ceria-based electrolytes, lanthanum gallate-­ based electrolytes, and bismuth oxide-based electrolytes. Zirconia combined with yttria (yttria-stabilized zirconia; YSZ) was the first oxygen ion conductor discovered by Nernst, as discussed above, and interestingly, is still the most commonly used electrolyte in SOFCs today. Although a number of materials are superior ionic conductors, YSZ electrolytes are second to none in terms of stability, exhibiting no detrimental electronic conductivity even under harsh reducing  The amount a given material will expand as the temperature increases.  Heated to high temperature to densify the components and ensure good adhesion between them. 1 2

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atmospheres at high temperature. Zirconia combined with scandium oxide has a higher ionic conductivity than YSZ, but the cost and availability of scandium have precluded its use as a commercially viable electrolyte (Ivers-Tiffée et al., 2001). Cerium oxide (ceria) combined with rare earth lanthanides (i.e. lanthanum, neodymium, gadolinium, samarium, dysprosium, erbium, ytterbium, lutetium) is a superior ionic conductor to YSZ, particularly at lower temperatures (800  °C), ceramic interconnects must be used. Typically this is lanthanum chromite doped with either calcium or strontium ((Ca-, Sr-)LaCrO3) (Fergus, 2004), although these require very high fabrication temperatures, high costs, and do not work well at lower temperatures due to decreasing electronic conductivity (Fergus, 2007). For lower temperatures, metal interconnects can be used. Siemens/ Plansee developed an alloy called Ducrolloy using chromium, iron, and yttria (94% Cr, 5% Fe and 1% Y2O3; Cr-5Fe-1Y2O3) (Badwal et al., 1997), which is suitable for higher temperature applications, but does suffer from relatively high cost and chromium poisoning of the electrode. As the temperature is decreased further, much cheaper ferritic steels can be used which consist primarily of iron with chromium addition (Wu & Liu, 2010). 4.2.5  Geometries and Fabrication SOFCs can be fabricated in several different geometries, as shown in Fig. 4.3. Typically, they are classified by both the shape and the component that supports the structure. Figure  4.3a shows a typically planer SOFC stack, with the interconnect providing the gas channels in the form of a bipolar plate. Figure 4.3b shows a tubular design, where the fuel gas is flowed through the centre of the tube and the oxidant surrounds the exterior. A third, and less common, geometry is in the form of micro-­ SOFCs (μSOFCs) as shown in Fig. 4.3c where the components are deposited as thin films on a silicon substrate for low power applications such as portable electronics (Bieberle-Hütter et al., 2008). The structural support of the SOFC usually comes from either the electrolyte, anode, or cathode, as shown schematically in Fig. 4.3d–f. Each design has its own benefits, although anode-supported cells are most common, especially in the planer geometry.

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Fig. 4.3  SOFC designs and geometries

A  significant challenge associated with SOFCs is that of fabrication. Each component requires high temperatures to manufacture (usually above 1000 °C, and much higher than the operating temperature) as well as to provide good cohesion between the various components. As such, all components must be compatible in terms of their chemical stability, thermal expansion, and mechanical compliance. The components must also be tolerant to impurities stemming from the sealing materials used to ensure the structure is gas tight. Manufacturing methods to fabricate components in the right geometry (thickness, porosity, etc.) at suitable temperatures is the subject of intensive research. Together these issues highlight the challenges of SOFC design. Even if new materials are developed with desirable intrinsic properties (ionic conductivity, electronic conductivity, etc.) substantial work is still required to integrate them  with existing components.

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4.3   Commercial Production and Applications of SOFCs The power output of an SOFC device is limited only by the size of the cell or number of cells in a stack, and therefore are scalable across a range of power generation applications ranging from portable electronics ( 4.0 kW/L

=> 5.0 kW/L

800 km 6.0 kW/L

15 years (passenger cars)

Over 15 years (passenger cars)

Over 15 years (passenger cars) Over 15 years (commercial cars)

–

–

Over 15 years (passenger cars) 15 years (commercial cars) –

5.7 wt%

6 wt%

–

–

More than 7 million yen

–

FC system (fuel cell About stacks) 20,000 yen/kW Hydrogen storage About system (with 5 kg 700,000 storage) yen Source: METI (2019)

Comparable to those of HEVs in the same class