Principles of Electrochemical Conversion and Storage Devices

Professor Kevin Huang is a SmartState Endowed Chair and Director of the Solid Oxide Fuel Cell Center at University of South Carolina. He teaches Advanced Thermodynamics and Energy Storage to graduate students. He is the associate editor of Journal of Electrochemical Energy Conversion and Storage. He is the recipient of numerous awards, including the 2018 Breakthrough Leadership in Research Award and the 2017 Educational Foundation Award for Research in Science, Mathematics, and Engineering.

• Preface xi1 Introduction 11.1 Brief History of Electrochemical Cells 21.2 Configuration of Electrochemical Cells 31.3 Half-Reactions in Electrochemical Cells 41.4 Faradaic and Non-Faradaic Reactions 51.5 Nernst Equation 61.6 Overpotential and Reaction Rate 71.7 Several Important Features of Electrochemical Cells 7References 8Problems 82 Thermodynamics of Electrochemical Cells 92.1 Open Electrochemical Cell Systems 92.1.1 Nernst Potential E n of Galvanic Cells 102.1.2 Thermoneutral Potential E tn of Electrolytic Cells 132.1.3 Thermodynamic Efficiency of Electrochemical Cells 152.2 Closed Electrochemical Cell Systems 162.2.1 E n of Batteries 162.2.2 Theoretical Energy Density of Battery Cells 172.2.3 Maximum Theoretical Charge Capacity of a Battery Cell 172.2.4 Round-Trip Efficiency of Battery Cell 182.3 Temperature Dependence of E n and E tn 182.4 Pressure Dependence of E n and E tn 202.5 Thermal and Chemical Expansion Coefficients 222.6 Heat Production and Consumption in Electrochemical Cells 232.7 Gibbs Phase Rule in Electrochemical Cells 25References 27Problems 283 Kinetics of Electrochemical Cells 293.1 Bulk Ionic Transport in Solid Inorganic Electrolytes (SIEs) 293.1.1 Ionic Conductivity 303.1.2 Extrinsic Ionic Conductors 313.1.3 Intrinsic Ionic Conductors 323.1.4 Random-Walk Theory 323.2 Ionic Transport in Solid Amorphous Electrolytes 343.3 Ionic Transport in Aqueous Solution Electrolytes 353.3.1 Basic Principles 353.3.2 Ideality versus Non-ideality 383.3.3 Walden’s Law 403.4 Comparison of Aqueous and Non-Aqueous Electrolytes 413.5 Kinetics of Electrode Reactions 413.5.1 Generic Rate of Electrode Kinetics 413.5.2 Potential-Dependent Rate of Electrode Kinetics 423.5.2.1 Standard Rate Constant k o 423.5.2.2 Exchange Current Density I O 433.5.2.3 Butler–Volmer Formulation 433.5.2.4 Mass Transfer Involved Activation Polarization 44References 45Problems 454 Fuel Cells and Electrolytic Cells 474.1 Fuel Cells/Electrolytic Cells Basics 474.2 Voltage Losses in FCs and ECs 494.2.1 Ohmic Voltage Loss 494.2.2 Activation Polarization 504.2.3 Concentration Polarization 524.2.3.1 Air-Electrode 534.2.3.2 Fuel-Electrode 564.2.3.3 Effect of Pressure 584.2.3.4 Coupled Activation and Concentration Polarizations 584.3 Efficiencies of Fuel Cells and Electrolytic Cells 594.3.1 Efficiency of Fuel Cells 594.3.2 Efficiency of Electrolytic Cells 614.4 Fuel Cells with Acidic Electrolytes 614.4.1 Pafc 614.4.1.1 Electrode Reactions 624.4.1.2 Cell Components 624.4.2 Pemfc 624.4.2.1 Electrode Reactions 624.4.2.2 Cell Components 624.4.2.3 Water Management 634.4.3 Solid Acid Fuel Cells 644.4.3.1 Electrode Reactions 644.4.3.2 Cell Components 654.5 Fuel Cells with Alkaline Electrolytes 654.5.1 Liquid Alkaline FC 654.5.1.1 Electrode Reactions 654.5.1.2 Cell Components 654.5.2 Anion-Exchange Membrane (AEM) FC 664.6 Fuel Cells with Molten Carbonate Electrolytes 664.6.1 Electrode Reactions 674.6.2 Components 674.6.2.1 Electrolyte 674.6.2.2 Electrolyte Matrix 674.6.2.3 Cathode 684.6.2.4 Fuel-Electrode (Anode) 694.6.2.5 Interconnect 694.6.2.6 Impurity Effect 694.7 Fuel Cells with Solid Oxide Electrolytes 694.7.1 Electrode Reactions 704.7.2 Components 704.7.2.1 Oxide-Ion-Conducting Electrolytes 714.7.2.2 Proton-Ion-Conducting Electrolytes 744.7.2.3 Air-Electrodes 754.7.2.4 Fuel-Electrodes 774.7.2.5 Interconnects 784.8 Electrolytic Cells 804.8.1 Co-Electrolysis of CO 2 and H 2 OtoSyngas 804.8.2 Electrochemical CO 2 Reduction Reaction (CO 2 RR) to Liquid Chemicals 814.8.2.1 CO 2 to Methanol Conversion 834.8.2.2 CO 2 to Formic Acid Conversion 834.8.2.3 CO 2 to CO Conversion 844.8.2.4 CO 2 to Methane Conversion 844.8.2.5 CO 2 to Ethanol Conversion 854.8.2.6 CO 2 to Ethylene Conversion 85References 86Problems 875 Batteries 895.1 Battery Basics 895.1.1 Discharge Curve Shape and Gibbs Phase Rule 895.1.2 Maximum Voltage and Energy Density of a Battery in General 915.1.3 Maximum Voltage and Energy Density of a Binary Conversion-Type Battery 915.1.4 Maximum Voltage and Energy Density of a Ternary Conversion-Type Battery 935.1.5 C-rate 945.1.6 Electrochemical Stability Window of Electrolytes 955.2 Rechargeable Batteries with Aqueous Electrolytes 965.2.1 Aqueous Batteries with Acidic Electrolytes 965.2.1.1 Lead Acid Battery (LAB) 965.2.1.2 All Vanadium Redox Flow Battery 985.2.2 Batteries with Alkaline Electrolytes and Ni-Based Cathode 995.2.2.1 Ni Cathode Chemistry 1005.2.2.2 “Memory” Effect of Ni-Cathode 1015.2.2.3 Ni–Cd Battery 1015.2.2.4 Ni–Zn Battery 1025.2.2.5 Ni–Fe Battery 1035.2.2.6 Ni-Metal Hydride (MH) Battery 1035.2.2.7 Alkaline Metal–Air Batteries 1045.2.2.8 Alkaline Redox Flow Batteries 1055.2.3 Batteries with Neutral Aqueous Electrolytes 1065.3 Rechargeable Batteries with Organic Electrolytes 1075.3.1 Organic Electrolytes 1085.3.2 The “Rocking-Chair” Battery Concept 1095.3.3 Intercalation Chemistry 1095.3.3.1 Intercalation/Insertion Reaction 1105.3.3.2 What Determines the Potential of a Redox Couple? 1115.3.3.3 Terminology for Describing Structures of Intercalatable/Insertable Compounds 1115.3.4 Intercalatable/Insertable Electrodes 1125.3.4.1 Cathodes 1125.3.4.2 Anodes 1135.3.5 Conversion Electrodes 1145.3.5.1 Cathodes 1155.3.5.2 Anodes 1155.3.5.3 Beyond Li-ion Chemistry 1165.4 Rechargeable Batteries with Solid Electrolytes 1165.4.1 Batteries with Oxide-Based Li-ion Conductors 1175.4.2 Batteries with Oxide-Based Na-Ion Conductors 1185.4.3 Battery with Oxide-Based Oxide-Ion Conductor 1205.4.3.1 Configuration and Working Principle 1205.4.3.2 Chemistry 1215.4.3.3 Performance Metrics of SOMARBs 1225.4.3.4 Kinetic Considerations of SOMARBs 1235.5 Primary Batteries 1245.5.1 Batteries with Aqueous Alkaline Electrolytes 1245.5.1.1 Zn-MnO 2 1245.5.1.2 Zn–Air 1255.5.2 Batteries with Organic Electrolytes and Li-Metal Anode 1265.5.2.1 Li-MnO 2 Battery 1265.5.2.2 Li–FeS 2 Battery 1265.5.2.3 Li–cf X Battery 1275.5.2.4 Li–SO 2 Battery 1285.5.2.5 Li-SOCl 2 1295.5.2.6 Li–AgV 2 O 5 129References 129Problems 1306 Capacitors 1316.1 Capacitor Basics 1316.1.1 Capacitance 1316.1.2 Dielectrics 1326.1.3 Capacitors in Electrical Circuits 1346.1.4 Capacitance from CV and GCD 1356.1.5 Capacitors for Electrical Energy Storage 1366.2 Parallel-Plate Capacitors (PPCs) 1376.3 Electrochemical Double-layer Capacitors (EDLCs) 1396.4 Electrochemical Pseudocapacitors (ECPCs) 1406.4.1 A Brief History of ECPCs 1416.4.2 ECPC Materials 1416.4.3 Types of ECPCs 1416.4.4 Electrochemical Signatures of ECPCs 142References 143Problems 1437 Basic Electrochemical Methods 1457.1 Controlled Potential Methods 1457.1.1 Constant Potential 1467.1.2 Potential Sweep 1477.1.2.1 Reversible Systems 1487.1.2.2 Totally Irreversible Systems 1497.1.2.3 Quasi-Reversible Systems 1507.1.2.4 Cyclic Voltammetry 1507.2 Controlled Current Methods 1507.2.1 Constant Current 1517.2.1.1 Reversible Electrode Reactions with Multi-electron Transfer 1527.2.1.2 Totally Irreversible Electrode Process 1527.2.1.3 Quasi-reversible Electrode Process 1537.2.2 Coulometric Titration 1537.3 Current Transient Method 1547.3.1 Galvanic Current Interruption 1547.3.2 Galvanic Intermittent Titration (GITT) 1557.4 Electrochemical Impedance Spectroscopy 1577.4.1 EIS Theory 1587.4.2 Experimental Setup 1617.5 Electrical Conductivity 1627.6 Electrical Conductivity Relaxation (ECR) Method 1647.7 Ion Transport Number of Electrolyte 1667.7.1 The Hittorf Method 1667.7.2 The Moving Boundary Method 1677.7.3 Concentration Cell Method 1697.7.4 Quartz Crystal Microbalance (QCM) Method 1697.7.5 Evans–Vincent–Bruce Method 170References 172Problems 172Appendix A Common Reference Electrodes and Potentials 175A.1 Calomel Electrodes 175A.2 Silver/Silver Chloride Electrodes 176A.3 Converting Potentials Between Reference Electrodes 177Appendix B Standard Electrode Potentials in Aqueous Solutions 179Appendix C Current Functions for Charge Transfer Process 189Appendix D Standard Gibbs Free Energy of Formation of Selected Compounds 193Reference 241Appendix E Standard Heat of Combustion of Common Fuels 243Appendix F Commonly Used Physical Constants 255Nomenclature 257Index 269