Solid Oxide Fuel Cells: From Electrolyte-Based to Electrolyte-Free Devices

Presents innovative approaches towards affordable, highly efficient, and reliable sustainable energy systems Written by leading experts on the subject, this book provides not only a basic introduction and understanding of conventional fuel cell principle, but also an updated view of the most recent developments in this field. It focuses on the new energy conversion technologies based on both electrolyte and electrolyte-free fuel cells?from advanced novel ceria-based composite electrolyte low temperature solid oxide fuel cells to non-electrolyte fuel cells as advanced fuel-to-electricity conversion technology. Solid Oxide Fuel Cells: From Electrolyte-Based to Electrolyte-Free Devices is divided into three parts. Part I covers the latest developments of anode, electrolyte, and cathode materials as well as the SOFC technologies. Part II discusses the non-electrolyte or semiconductor-based membrane fuel cells. Part III focuses on engineering efforts on materials, technology, devices and stack developments, and looks at various applications and new opportunities of SOFC using both the electrolyte and non-electrolyte principles, including integrated fuel cell systems with electrolysis, solar energy, and more. -Offers knowledge on how to realize highly efficient fuel cells with novel device structures -Shows the opportunity to transform the future fuel cell markets and the possibility to commercialize fuel cells in an extended range of applications -Presents a unique collection of contributions on the development of solid oxide fuel cells from electrolyte based to non-electrolyte-based technology -Provides a more comprehensive understanding of the advances in fuel cells and bridges the knowledge from traditional SOFC to the new concept -Allows readers to track the development from the conventional SOFC to the non-electrolyte or single-component fuel cell Solid Oxide Fuel Cells: From Electrolyte-Based to Electrolyte-Free Devices will serve as an important reference work to students, scientists, engineers, researchers, and technology developers in the fuel cell field.

Table of Contents:
Preface xiii Part I Solid Oxide Fuel Cell with Ionic Conducting Electrolyte 1 1 Introduction 3 Bin Zhu and Peter D. Lund 1.1 An Introduction to the Principles of Fuel Cells 3 1.2 Materials and Technologies 5 1.3 New Electrolyte Developments on LTSOFC 10 1.4 Beyond the State of the Art: The Electrolyte-Free Fuel Cell (EFFC) 20 1.4.1 Fundamental Issues 23 1.5 Beyond the SOFC 25 References 28 2 Solid-State Electrolytes for SOFC 35 Liangdong Fan 2.1 Introduction 35 2.2 Single-Phase SOFC Electrolytes 37 2.2.1 Oxygen Ionic Conducting Electrolyte 37 2.2.1.1 Stabilized Zirconia 37 2.2.1.2 Doped Ceria 39 2.2.1.3 SrO- and MgO-Doped Lanthanum Gallates (LSGM) 42 2.2.2 Proton-Conducting Electrolyte and Mixed Ionic Conducting Electrolyte 42 2.2.3 Alternative New Electrolytes and Research Interests 44 2.3 Ion Conduction/Transportation in Electrolytes 49 2.4 Composite Electrolytes 52 2.4.1 Oxide–Oxide Electrolyte 52 2.4.2 Oxide–Carbonate Composite 53 2.4.2.1 Materials Fabrication 54 2.4.2.2 Performance and Stability Optimization 57 2.4.3 Other Oxide–Salt Composite Electrolytes 60 2.4.4 Ionic Conduction Mechanism Studies of Ceria–Carbonate Composite 62 2.5 NANOCOFC and Material Design Principle 66 2.6 Concluding Remarks 67 Acknowledgments 69 References 69 3 Cathodes for Solid Oxide Fuel Cell 79 Tianmin He, Qingjun Zhou, and Fangjun Jin 3.1 Introduction 79 3.2 Overview of Cathode Reaction Mechanism 80 3.3 Development of Cathode Materials 82 3.3.1 Perovskite Cathode Materials 82 3.3.1.1 Mn-Based Perovskite Cathodes 83 3.3.1.2 Co-Based Perovskite Cathodes 85 3.3.1.3 Fe-Based Perovskite Cathodes 88 3.3.1.4 Ni-Based Perovskite Cathodes 89 3.3.2 Double Perovskite Cathode Materials 89 3.4 Microstructure Optimization of Cathode Materials 94 3.4.1 Nanostructured Cathodes 94 3.4.2 Composite Cathodes 97 3.5 Summary 102 References 103 4 Anodes for Solid Oxide Fuel Cell 113 Chunwen Sun 4.1 Introduction 113 4.2 Overview of Anode Reaction Mechanism 114 4.2.1 Basic Operating Principles of a SOFC 114 4.2.1.1 The Anode Three-Phase Boundary 115 4.3 Development of Anode Materials 117 4.3.1 Ni–YSZ Cermet Anode Materials 117 4.3.2 Alternative Anode Materials 118 4.3.2.1 Fluorite Anode Materials 118 4.3.2.2 Perovskite Anode Materials 120 4.3.3 Sulfur-Tolerant Anode Materials 124 4.4 Development of Kinetics, Reaction Mechanism, and Model of the Anode 126 4.5 Summary and Outlook 135 Acknowledgments 137 References 137 5 Design and Development of SOFC Stacks 145 Wanbing Guan 5.1 Introduction 145 5.2 Change of Cell Output Performance Under 2D Interface Contact 145 5.2.1 Design of 2D Interface Contact Mode 145 5.2.2 Variations of Cell Output Performance Under 2D Contact Mode 147 5.2.3 2D Interface Structure Improvements and Enhancement of Cell Output Performance 149 5.2.4 Contributions of 3D Contact in 2D Interface Contact 151 5.2.5 Mechanism of Performance Enhancement After the Transition from 2D to 3D Interface 153 5.3 Control Design of Transition from 2D to 3D Interface Contact and Their Quantitative Contribution Differentiation 156 5.3.1 Control Design of 2D and 3D Interface Contact 156 5.3.2 Quantitative Effects of 2D Contact on the Transient Output Performance of a Cell 158 5.3.3 Quantitative Effects of 2D Contact on the Steady-State Output Performance of the Cell 161 5.3.4 Quantitative Effects of 3D Contact on Cell Transient Performance 163 5.3.5 Quantitative Effects of 3D Contact on the Steady-State Performance of a Cell 166 5.3.6 Differences Between 2D and 3D Interface Contacts 169 5.4 Conclusions 171 References 172 Part II Electrolyte-Free Fuel Cells: Materials, Technologies, and Working Principles 173 6 Electrolyte-Free SOFCs: Materials, Technologies, and Working Principles 175 Bin Zhu, Liangdong Fan, Jung-Sik Kim, and Peter D. Lund 6.1 Concept of the Electrolyte-Free Fuel Cell 175 6.2 SLFC Using the Ionic Conductor-based Electrolyte 177 6.3 Developments on Advanced SLFC 179 6.4 From SLFCs to Semiconductor–Ionic Fuel Cells (SIFCs) 184 6.5 The SLFC Working Principle 196 6.6 Remarks 204 Acknowledgments 207 References 207 7 Ceria Fluorite Electrolytes from Ionic to Mixed Electronic and Ionic Membranes 213 Baoyuan Wang, Liangdong Fan, Yanyan Liu, and Bin Zhu 7.1 Introduction 213 7.2 Doped Ceria as the Electrolyte for Intermediate Temperature SOFCs 214 7.3 Surface Doping for Low Temperature SOFCs 216 7.4 Non-doped Ceria for Advanced Low Temperature SOFCs 222 References 235 8 Charge Transfer in Oxide Solid Fuel Cells 239 Jing Shi and Sining Yun 8.1 Oxygen Diffusion in Perovskite Oxides 239 8.1.1 Oxygen Vacancy Formation 239 8.1.2 Oxygen Diffusion Mechanisms 242 8.1.3 Anisotropy Oxygen Transport in Layered Perovskites 244 8.1.3.1 Oxygen Transport in Ruddlesden–Popper (RP) Perovskites 244 8.1.3.2 Oxygen Transport in A-Site Ordered Double Perovskites 244 8.1.4 Oxygen Ion Diffusion at Grain Boundary 246 8.1.5 Factors Controlling Oxygen Migration Barriers in Perovskites 248 8.2 Proton Diffusion in Perovskite-Type Oxides 249 8.2.1 Proton Diffusion Mechanisms 249 8.2.2 Proton–Dopant Interaction 253 8.2.2.1 Influence of Dopants in A-site 253 8.2.2.2 Influence of Dopants in B-Site 254 8.2.3 Long-range Proton Conduction Pathways in Perovskites 255 8.2.4 Hydrogen-Induced Insulation 256 8.3 Enhanced Ion Conductivity in Oxide Heterostructures 259 8.3.1 Enhanced Ionic Conduction by Strain 259 8.3.2 Enhanced Ionic Conductivity by Band Bending 263 8.3.2.1 Surface State-induced Band Bending 263 8.3.2.2 Band Bending in p–n Heterojunctions 265 8.3.2.3 p–n Heterojunction Structures in SOFC 265 8.4 Summary 266 Acknowledgments 267 References 267 9 Material Development II: Natural Material-based Composites for Electrolyte Layer-free Fuel Cells 275 Chen Xia and Yanyan Liu 9.1 Introduction 275 9.1.1 Materials Development for EFFCs 275 9.1.2 Natural Materials as Potential Electrolytes 276 9.2 Industrial-grade Rare Earth for EFFCs 279 9.2.1 Rare-earth Oxide LCP 280 9.2.2 Semiconducting–Ionic Composite Based on LCP 281 9.2.2.1 LCP–LSCF 282 9.2.2.2 LCP–ZnO 284 9.2.3 Stability Operation and Schottky Junction of EFFC 288 9.2.3.1 Performance Stability 288 9.2.3.2 In Situ Schottky Junction Effect 288 9.2.4 Summary 290 9.3 Natural Hematite for EFFCs 291 9.3.1 Natural Hematite 292 9.3.2 Semiconducting–Ionic Composite Based on Hematite 295 9.3.2.1 Hematite–LSCF 295 9.3.2.2 Hematite/LCP–LSCF 297 9.3.3 Summary 300 9.4 Natural CuFe Oxide Minerals for EFFCs 302 9.4.1 Natural CuFe2O4 Mineral for EFFC 302 9.4.2 Natural Delafossite CuFeO2 for EFFC 305 9.4.3 Summary 308 9.5 Bio-derived Calcite for EFFC 308 9.5.1 Bio-derived Calcite for EFFC 309 9.5.2 Summary 312 References 314 10 Charge Transfer, Transportation, and Simulation 319 Muhammad Afzal, Mustafa Anwar, Muhammad I. Asghar, Peter D. Lund, Naveed Jhamat, Rizwan Raza, and Bin Zhu 10.1 Physical Aspects 319 10.2 Electrochemical Aspects 320 10.3 Ionic Conduction Enhancement in Heterostructure Composites 321 10.4 Charge Transportation Mechanism and Coupling Effects 326 10.5 Surface and Interfacial State-Induced Superionic Conduction and Transportation 330 10.6 Ionic Transport Number Measurements 331 10.7 Determination of Electron and Ionic Conductivities in EFFCs 332 10.8 EIS Analysis 334 10.9 Semiconductor Band Effects on the Ionic Conduction Device Performance 335 10.10 Simulations 339 Acknowledgments 343 References 343 11 Electrolyte-Free Fuel Cell: Principles and Crosslink Research 347 Yan Wu, Liangdong Fan, Naveed Mushtaq, Bin Zhu, Muhammad Afzal, Muhammad Sajid, Rizwan Raza, Jung-Sik Kim, Wen-Feng Lin, and Peter D. Lund 11.1 Introduction 347 11.2 Fundamental Considerations of Fuel Cell Semiconductor Electrochemistry 353 11.2.1 Physics and Electrochemistry at Interfaces 353 11.2.2 Electrochemistry vs. Semiconductor Physics 355 11.3 Working Principle of Semiconductor-Based Fuel Cells and Crossing Link Sciences 356 11.4 Extending Applications by Coupling Devices 367 11.5 Final Remarks 368 Acknowledgments 372 References 373 Part III Fuel Cells: From Technology to Applications 377 12 Scaling Up Materials and Technology for SLFC 379 Kang Yuan, Zhigang Zhu, Muhammad Afzal, and Bin Zhu 12.1 Single-Layer Fuel Cell (SLFC) Engineering Materials 379 12.2 Scaling Up Single-Layer Fuel Cell Devices: Tape Casting and Hot Pressing 383 12.3 Scaling Up Single-Layer Fuel Cell Devices: Thermal Spray Coating Technology 386 12.3.1 Traditional Plasma Spray Coating Technology 387 12.3.2 New Developed Low-Pressure Plasma Spray (LPPS) Coating Technology 388 12.4 Short Stack 395 12.4.1 SLFC Cells 395 12.4.2 Bipolar Plate Design 396 12.4.3 Sealing and Sealant-Free Short Stack 396 12.5 Tests and Evaluations 397 12.6 Durability Testing 399 12.7 A Case Study for the Cell Degradation Mechanism 400 12.8 Continuous Efforts and Future Developments 404 12.9 Concluding Remarks 409 References 411 13 Planar SOFC Stack Design and Development 415 Shaorong Wang, Yixiang Shi, Naveed Mushtaq, and Bin Zhu 13.1 Internal Manifold and External Manifold 415 13.2 Interface Between an Interconnect Plate and a Single Cell 416 13.3 Antioxidation Coating of the Interconnect Plate 418 13.4 Design the Flow Field of Interconnect Plate 419 13.4.1 Mathematical Simulation 420 13.4.2 Effect of Co-flow, Crossflow, and Counterflow 422 13.4.3 Air Flow Distribution Between Layers in a Stack 424 13.5 The Importance of Sealing 424 13.5.1 Thermal Cycling of the Sealing 428 13.5.2 Durability of Sealing 428 13.6 The Life of the Stack: The Chemical Problems on the Interface 429 13.7 Toward Market Products 431 13.8 Concluding Remarks 443 References 443 14 Energy System Integration and Future Perspectives 447 Ghazanfar Abbas, Muhammad Ali Babar, Fida Hussain, and Rizwan Raza 14.1 Solar Cell and Fuel Cell 447 14.2 Fuel Cell–Solar Cell Integration 450 14.3 Solar Electrolysis–Fuel Cell Integration 452 14.4 Fuel Cell–Biomass Integration 453 14.5 The Fuel Cell System Modeling Using Biogas 454 14.5.1 Activation Loss 457 14.5.2 Ohmic Loss 457 14.5.3 Concentration Voltage Loss 458 14.6 The Fuel Cell System Efficiency (Heating and Electrical) 458 14.6.1 The Effect of Different Temperatures on System Efficiency 458 14.6.2 The Fuel Utilization Factor and Efficiencies of the System 458 14.6.3 The System Efficiencies and Operating Pressure 460 14.7 Integrated New Clean Energy System 460 14.8 Summary 462 References 462 Index 465

About the Author :
Bin Zhu, PhD, moved from KTH, Sweden as a Chief Scientist (Professor Director) of Energy Storage Joint Research Center, Southeast University, China. He has published more than 300 scientifc papers in nano-composite ionic conductors and new semiconductor-ionic materials for advanced fuel cells. Rizwan Raza, PhD, is Assistant Professor in the Department of Physics in COMSATS Institute of Information Technology, Pakistan. He has published more than 100 scientific papers. Liangdong Fan, PhD, is Lecturer in the College of Chemistry and Environmental Engineering at Shenzhen University, China. His interests focus on novel nanocomposite functional materials for fuel cells and electro-catalysis. Chunwen Sun is a Professor at Beijing Institute of Nanoenergy and Nanosystems (BINN), Chinese Academy of Sciences (CAS). His research interests include energy storage and conversion, e.g., lithium/sodium-ion batteries, metal-air batteries, all-solid-state batteries, fuel cells and self-power systems.