Introduction to Fuel Cells San Ping Jiang · Qingfeng Li Introduction to Fuel Cells Electrochemistry and Materials SanPingJiang Qingfeng Li WA School of Mines: Minerals, Energy Department of Energy Conversion and Chemical Engineering and Storage Curtin University Technical University of Denmark Perth, WA, Australia Lyngby, Denmark ISBN 978-981-10-7625-1 ISBN 978-981-10-7626-8 (eBook) https://doi.org/10.1007/978-981-10-7626-8 © Springer Nature Singapore Pte Ltd. 2022 This work is subject to copyright. All rights are reserved 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. 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The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore Preface Fuel cells were initially developed for the space mission programs in 1960s and have today well demonstrated for automobiles, portable electronics, and large-scale power generation plants. The development has appreciably endorsed by the ever-growing concern of fossil fuel depleting and global warming, and in the last years by the potential synergies with renewable energies and the future hydrogen economy. There are quite a number of fuel cell books available in the market. A majority of the books are technically orientated, aimed at updating the detailed progress from material science, kinetic mechanisms, characterization methodologies to techno- logical integration of membrane-electrode assemblies, stacks, fuel processors, and system demonstration. These types of books are interdisciplinary including thematic monographs, symposium proceedings, and a variety of comprehensive handbooks. They are written by fuel cell experts and scientists and suitable for the reader of researchers, professional engineers, and other fuel cell workers in the field. As the interest in fuel cells diffuses well beyond the scientific and technical community, the fuel cell topics is of daily discussion in news media and popular teaching courses in university campuses. The fundamental principles of fuel cells are covered by several well-written textbooks. This type of books is introducing thermodynamics, basic electrochemistry, functional materials, components, perfor- mance, and applications. They are suitable for the reader of varied engineering back- grounds to learn what fuel cells are, how fuel cells work, and why they offer the high efficiency, zero emission, and potential sustainability. There is a need for fuel cell textbooks to fill up the gap in between. One, for example, outlines the field at a fundamental thermodynamics, electrochemistry, and material level that can be understood by those who are new in the field with a general engineering background, while the content is advanced enough to provide essential knowledge of technical and material insights for those who are doing or wish to do research in the field. This is what the authors of the present book have attempted to do. Both authors of the book have been doing research and teaching fuel cell courses for more than thirty years. A difficulty encountered in teaching is the lack of examples and problems in fuel cells, which are essential to bridge between the basic knowledge v vi Preface and skill to handle practical problems for students and engineers. It is therefore attempted to include illustrative and practical examples and problems through the chapters of this book. From numerous examples and referecenes, readers can also find detailed information in the experimental design and techniques commonly used in the studies of fuel cells. The book is organized in four parts. Part I of the book is a brief introduc- tion of fundamentals, though in a practical way, of fuel cells including thermody- namics, electrochemistry, and fueling scenarios. The other three parts of the book are devoted to fuel cell technologies. Of types of the technologies, emphasis is placed on polymer electrolyte membrane fuel cells (Part II) and solid oxide fuel cells (Part III), each covering principle and materials, reaction, characterization, microstructure, and fabrication. Many examples of procedures and protocols are from our own lab prac- tice while well selected information from literature is also provided. The last part of the book presents the rest types of fuel cells, i.e., alkaline fuel cells, phosphoric acid fuel cells, molten carbonate fuel cells, and the emerging type of protonic ceramic fuel cells, microbial fuel cells, and biofuel cells. The book would not be finished without help and contributions from past and present colleagues, students, research fellows, and collaborators of both authors who would like to take this opportunity to thank: • Prof. Chen Kongfa and Dr. Ai Na of Fuzhou University; Dr. Zhang Lan of Nanyang Technological University; Prof. Cheng Yi of Central South University; Prof. Zhao Ling of China University of Geosciences; Prof. He Tianmin of Jilin University; Dr. Zhang Jin and Prof. Lu Shanfu of Beihang University; Dr. He Shuai of University of St. Andrew; and Dr. Liu Yu, Dr. Zhao Shiyong, Dr. Zhang Xiao, Ms. Sun Yi and Ms. Zhang Xiaoran of Curtin University for providing raw materials and numerous drawings • Prof. Li Jian and Prof. Pu Jian of Huazhong University of Science and Technology; Prof. Shao Zongping of Curtin University; and Prof. John Zhu of Queensland University for valuable comments and suggestions on the SOFC chapters • Prof. Gordon Parkinson of Curtin University for painstakingly reading and editing of the book chapters • Prof. Jens Oluf Jensen for sharing a lecturing course (hydrogen energy and fuel cells) in last 18 year at DTU from which one of the authors has received many inspiration in writing this book • Dr. Lars N. Cleemann, Dr. Erik Christensen, and Dr. David Aili for sharing an experimental course (hydrogen and fuel cell chemistry) at DTU for the last 15 years. The teaching materials have been the basis for some of the chapter content • Dr. David Aili and Dr. Yang Hu for reading and commenting book chapters and providing graphs. These acknowledgements would not be complete without thanking our family members. SPJ would like to take this opportunity to thank his wife, Choo, his life companion for 30 years, for taking care of all other aspects of his life while he was involved in writing this book. Prof. Jiang would also like to thank his three beautiful children, Yin, Weiping, and Danhua, for the understanding, patience, and Preface vii support. QL would like to thank his family, wife Tianqing and son Mike, for their understanding and constant supportive presence through the time spent on writing this book. Without their encouragement and support, this book would not be possible. Last but not least, the publication of the book would not be possible without the encouragement and help from the editorial staff at Springer and special thanks go to June Tong for the initiation of the project, Umamagesh A P, Sridevi Purushothaman, Sunny Guo, and Nobuko Hirota for the constant support and conductive environment for pursuing this type of project. Perth, Australia San Ping Jiang Lyngby, Denmark Qingfeng Li Contents Part I Fundamentals 1 Introduction .................................................. 3 1.1 Fuel Cells in the Hydrogen Chain . 3 1.2 A Brief History of Fuel Cells . 5 1.3 Types, Construction, and Components of Fuel Cells . 8 1.3.1 Fuel Cell Classification . 8 1.3.2 Construction and Components of Fuel Cells . 9 1.3.3 Brief Summary of Each Type of Fuel Cells . 12 1.4 Fuel Cells Versus Batteries . 16 1.5 Unitized Regenerative Fuel Cells and Reversible Fuel Cells . 17 1.6 Applications and Prospect of Fuel Cell Technologies . 19 1.7 Summary ............................................... 23 1.8 Questions ............................................... 24 1.9 General Readings . 25 References . 25 2 Fuel Cell Thermodynamics ..................................... 27 2.1 Internal Energy, Heat, Work, and Entropy . 27 2.2 EnthalpyandGibbsFreeEnergy ........................... 31 2.2.1 Definition of Enthalpy and Gibbs Free Energy . 31 2.2.2 Gibbs Free Energy from First and Second Thermodynamics Laws . 32 2.2.3 EnthalpyofFormation............................ 33 2.2.4 Effect of Temperature on the Change in Enthalpy andEntropy..................................... 36 2.2.5 Effect of Temperature on Gibbs Free Energy . 40 2.2.6 Gibbs Free Energy and Electrical Work . 41 2.2.7 Thermodynamic Reversible Potential