Physical Chemistry of Ionic Materials

Joachim Maier, PhD, is Director of the Max Planck Institute for Solid State Research, Stuttgart, Germany, a position he has held since 1991. He has lectured at elite universities in both Europe and the United States, and his work in pioneering the field of nanoionics has earned him numerous international awards and distinctions.

Preface to the Second Edition ix

Preface to the First Edition xi

1 Introduction 1

1.1 Motivation 1

1.2 The Defect Concept: Point Defects as the Main Actors 3

References 11

2 Bonding Aspects: From Atoms to Solid State 13

2.1 Chemical Bonding in Simple Molecules 13

2.1.1 Ideal Covalent Bonding 13

2.1.2 Polar Covalent Bonding 17

2.1.3 The Ionic Bonding 19

2.1.4 Metallic Bonding 20

2.1.5 Further Intermediate Forms of Chemical Bonding 21

2.1.6 Two-Body Potential Functions 21

2.2 Many Atoms in Contact: The Solid State as a Giant Molecule 23

2.2.1 The Band Model 23

2.2.2 Ionic Crystals 36

2.2.3 Molecular Crystals 41

2.2.4 Covalent Crystals 43

2.2.5 Metallic Crystals 44

2.2.6 Mixed Forms of Bonding in Solids 46

2.2.7 Crystal Structure and Solid State Structure 47

2.2.8 Atomistic Modelling 49

References 51

3 Phonons 55

3.1 Einstein and Debye models 55

3.2 Deviations From Ideality 58

References 61

4 Equilibrium Thermodynamics of the Perfect Solid 63

4.1 Preliminary Remarks 63

4.2 The Formalism of Equilibrium Thermodynamics 63

4.3 Examples of Equilibrium Thermodynamics 76

4.3.1 Solid–Solid Phase Transition 76

4.3.2 Melting and Evaporation 77

4.3.3 Solid–Solid Reaction 78

4.3.4 Solid–Gas Reaction 78

4.3.5 Phase Equilibria and Mixing Reactions 79

4.3.6 Spatial Equilibria in Inhomogeneous Systems 88

4.3.7 Thermodynamics of Elastically Deformed Solids 90

4.3.8 The Thermodynamic Functions of State of the Perfect Solid 91

References 93

5 Equilibrium Thermodynamics of the Real Solid 95

5.1 Preliminary Remarks 95

5.2 Equilibrium Thermodynamics of Point Defect Formation 96

5.3 Equilibrium Thermodynamics of Electronic Defects 110

5.4 Higher-Dimensional Defects 119

5.4.1 Equilibrium Concentration 119

5.4.2 Dislocations: Structure and Energetics 120

5.4.3 Interfaces: Structure and Energetics 124

5.4.4 Interfacial Thermodynamics and Local Mechanical Equilibria 130

5.5 Point Defect Reactions 139

5.5.1 Simple Internal Defect Equilibria 139

5.5.2 External Defect Equilibria 143

5.6 Doping and Freezing Effects 158

5.7 Interactions Between Defects 179

5.7.1 Associates 179

5.7.2 Activity Coefficients 187

5.8 Boundary Layers 194

5.8.1 General 194

5.8.2 Concentration Profiles in the Space Charge Zones 200

5.8.3 Conductivity Effects 204

5.8.4 Defect Thermodynamics of Interface: The Core-Space Charge Picture 209

5.8.5 Examples and Supplementary Comments 216

References 234

6 Kinetics and Irreversible Thermodynamics 243

6.1 Transport and Reaction 243

6.1.1 Transport and Reaction in the Light of Irreversible Thermodynamics 244

6.1.2 Transport and Reaction in the Light of Chemical Kinetics 249

6.2 Electrical Mobility 256

6.2.1 Ion Mobility 256

6.2.2 Electron Mobility 265

6.3 Phenomenological Diffusion Coefficients 267

6.3.1 Ion Conduction and Self-Diffusion 268

6.3.2 Tracer Diffusion 269

6.3.3 Chemical Diffusion 272

6.3.4 A Comparison of the Phenomenological Diffusion Coefficients 276

6.4 Concentration Profiles 278

6.5 Diffusion Kinetics of Stoichiometry Change 282

6.6 Complications of Matter Transport 289

6.6.1 Internal Interactions 289

6.6.2 Diffusion in Multicomponent Systems 300

6.6.3 Chemical Diffusion and Electrochemical Storage 301

6.6.4 Boundary Layers and Grain Boundaries 301

6.7 Surface Reactions 308

6.7.1 Elementary Processes 308

6.7.2 Coupled Reactions 310

6.7.3 Phenomenological Rate Constants 315

6.7.4 Reactivity, Chemical Resistance and Chemical Capacitance 328

6.8 Catalysis 329

6.9 Solid State Reactions 333

6.9.1 Fundamental Principles 333

6.9.2 Morphological and Mechanistic Complications 343

6.10 Processes Under Illumination 346

6.11 Nonlinear Phenomena 352

6.11.1 Irreversible Thermodynamics and Chemical Kinetics far From Equilibrium, and the Special Role of Autocatalysis 352

6.11.2 Nonequilibrium Structures in Time and Space 357

6.11.3 The Concept of Fractal Geometry 363

References 368

7 Solid State Electrochemistry I: Measurement Techniques 379

7.1 Preliminary Remarks 379

7.1.1 Current and Voltage in the Light of Defect Chemistry 379

7.1.2 Electrochemical Measurement Cells 383

7.2 Open Circuit Cells 384

7.2.1 Equilibrium Cells: Thermodynamic Measurements 384

7.2.2 Permeation Cells and Chemical Polarization: Measurement of Transport Parameters 390

7.3 Polarization Cells 395

7.3.1 Dielectric and Interfacial Polarization 397

7.3.2 Stoichiometry Polarization 414

7.3.3 Impedance Spectroscopy 427

7.3.4 Cyclic Voltammetry 437

7.3.5 Inhomogeneities and Heterogeneities: Many-Point Measurements and Point Electrodes 440

7.4 Coulometric Titration Cells 448

References 451

8 Solid State Electrochemistry II: Applications and Devices 457

8.1 Sensors, Actuators and Related Devices 457

8.1.1 Electrochemical Sensors 458

8.1.2 Electrochemical Actuators 464

8.2 Electrochemical Devices for Energy Conversion and Storage 467

8.2.1 Cells Generating Current: General 467

8.2.2 Fuel Cells 470

8.2.3 Batteries 477

8.2.4 Supercapacitors 495

8.2.5 Photoelectrochemical Devices 496

8.3 Bioelectrochemical Elements 498

8.4 Outlook 500

References 501

9 Nanoionics 507

9.1 Thermodynamic Aspects of Nanoparticles 508

9.2 Charge Carrier Thermodynamics in Nanosystems 516

9.3 Ion and Mass Transport Involving Interfaces 517

9.3.1 Ion Transport: Semi-Infinite 517

9.3.2 Ion Transport: Mesoscopic 520

9.3.3 Ion Transport: Mesoscopic Phase Transition 524

9.3.4 Fluoride Heterolayers 526

9.3.5 Nanocrystalline Oxides 531

9.3.6 Chemical Diffusion in Nano-Systems 535

9.4 Storage in Nanoparticles and Nanocomposites 536

9.4.1 Thermodynamics and Kinetics of Storage in Nanoparticles 536

9.4.2 Thermodynamics and Kinetics of Storage at Interfaces 539

9.4.3 Storage and Nano-Morphology 545

9.5 Nanoionics: Beyond Solid State Ionics Applications 546

9.6 Pushing Nanoionics to the Limits 547

References 549

Index 555