Solid Electrolytes and Their Applications

ISBN-13: 9781461330837 / Angielski / Miękka / 2011 / 298 str.

E. Subbarao

Opis

Defect solid state has been an area of major scientific and technological interest for the last few decades, the resulting important applications sus taining this interest. Solid electrolytes represent one area of defect solid state. The early work on defect ionic crystals and, in particular, the classic results of Kiukkola and Wagner in 1957 on stabilized zirconia and doped thoria laid the foundation for a systematic study of solid electrolytes. In the same year, Ure reported on the ionic conductivity of calcium fluoride. Since then, intense worldwide research has advanced our understanding of the defect structure and electrical conductivity of oxygen ion conductors such as doped zirconia and thoria and of the fluorides. This paved the way for thermo dynamic and kinetic studies using these materials and for technological applications based on the oxygen ion conductors. In the last few years we have seen the emergence of two new classes of solid electrolytes of great signifi cance: the fJ-aluminas and the silver ion conductors. The significance of these discoveries is that now (i) solid electrolytes are available which at room temperature exhibit electrical conductivity comparable to that of liquid electrolytes, (ii) useful electrical conductivity values can be achieved over a wide range of temperature and ambient conditions, and (iii) a wide variety of ions are available as conducting species in solids. The stage is therefore set for a massive effort at developing applications."

Spis treści

1. Defect Structure and Transport Properties.- 1. Introduction.- 2. Defect Structure.- 2.1. Types of Point Defects.- 2.2. Lattice Disorder and Association of Defects.- 2.3. Defect Equilibria.- 2.4. Energy of Formation and Motion of Defects.- 3. Experimental Methods.- 3.1. Density.- 3.2. X-Ray and Neutron Diffraction.- 3.3. Electrical Conductivity and Diffusion.- 3.4. Polarization Measurements.- 3.5. Impedance Measurement.- 3.6. Thermoelectric Power.- 3.7. Relaxation Methods.- 3.8. Miscellaneous Techniques.- 4. Materials.- 4.1. Fluorite-Type Oxides.- 4.2. ?-Alumina-Type Oxides.- 4.3. Silver-Iodide-Type Materials.- 4.4. Fluorides.- 4.5. Miscellaneous.- 5. Concluding Remarks.- References.- 2. Limiting Factors in Measurements Using Solid Electrolytes.- 1. Introduction.- 2. Electronic Conduction in the Electrolyte.- 2.1. Examples from Thermodynamic Measurements.- 2.2. Examples from Kinetic Measurements.- 3. Maintaining a Desired Chemical Potential at the Electrode-Electrolyte Interface.- 3.1. Influence of Electronic Conductivity.- 3.2. Influence of Chemical Reactions.- 3.3. Influence of the Gaseous Atmosphere.- 3.4. Equilibration of the Electrode Constituents.- 3.5. Polarization Effects at the Electrode-Electrolyte Interface.- 4. Effects of Porosity, Inhomogeneity, and Inadequate Mechanical Properties.- 5. Experimental Uncertainties.- 5.1. Limited Temperature Range of Study.- 5.2. Instrumentation Problems.- 6. Concluding Remarks.- References.- 3. Thermodynamic Studies of Alloys and Intermetallic Compounds.- 1. Introduction.- 1.1. General.- 1.2. Solid Electrolyte Galvanic Cell Method.- 1.3. Limitations of Data Derived from emf Measurements.- 2. Metallic Alloy Systems.- 2.1. Introduction.- 2.2. Binary Solid Metallic Alloys.- 2.3. Binary Liquid Alloys.- 2.4. Conclusion.- 3. Oxygen Dissolved in Metals and Alloys.- 3.1. Introduction.- 3.2. Dilute Alloys of Oxygen in Metals.- 3.3. Effect of Third Alloying Element on the Oxygen Activity.- 4. Fluoride Cells to Study Carbides, Borides, Phosphides, and Sulfides.- 5. Conclusion.- References.- 4. Thermodynamic Properties of Oxide Systems.- 1. Introduction.- 2. Comparison of the Solid Electrolyte Method with Other Methods for Thermodynamic Measurements.- 3. Types of Solid Electrolytes Used in the Study of Oxide Systems.- 4. Thermodynamic Measurements of Oxide Systems with Cells Involving Oxide Solid Electrolytes.- 4.1. Apparatus.- 4.2. Determination of the Free Energy of Formation of Oxides, Spinels, Silicates, and Other Compounds.- 4.3. Activity Measurements in Oxide Systems.- 4.4. Study of the Nonstoichiometry of Metallic Oxides.- 4.5. Some Special Studies of Oxides and Related Systems.- 5. Thermodynamic Measurements of Oxide Systems with Cells Involving Fluoride Solid Electrolytes.- 5.1. Introduction.- 5.2. Free Energy of Formation of Oxide Compounds.- 5.3. Measurement of Activities in Oxide Solid Solutions.- 6. Concluding Remarks.- References.- 5. Kinetic Studies.- 1. Introduction.- 2. Polarization Studies.- 2.1. Polarization Studies Involving Gaseous Electrodes.- 2.2. Polarization Studies Involving Liquid Electrodes.- 2.3. Polarization Studies Involving Solid Electrodes.- 2.4. Choice of Electrodes.- 3. Diffusion Measurements.- 3.1. Potentiostatic Techniques.- 3.2. Galvanostatic Techniques.- 3.3. Potentiometric Techniques.- 3.4. Combined Potentiostatic and Potentiometric Techniques.- 3.5. Evaluation of Experimental Techniques.- 4. Kinetics of Phase-Boundary and Diffusion-Controlled Reactions.- 4.1. Phase-Boundary Reactions.- 4.2. Diffusion-Controlled Reactions.- 5. Concluding Remarks.- References.- 6. Technological Applications of Solid Electrolytes.- 1. General.- 1.1. Introduction.- 1.2. Classification of Technological Applications.- 2. Oxygen Meters.- 2.1. Introduction.- 2.2. Determination of Oxygen in Gases.- 2.3. Measuring and Recording.- 2.4. Estimation of Gas Composition from po2 Measurement.- 2.5. Industrial Applications.- 2.6. Oxygen Determination in Liquid Metals.- 2.7. Determination of Oxygen in Liquid Steel.- 3. Oxygen Transfer to and from Materials.- 3.1. Introduction.- 3.2. Oxygen Pump and Probe.- 3.3. Coulometric Control of Oxygen in Liquid Metals.- 3.4. Other Applications.- 4. Energy Conversion.- 4.1. Introduction.- 4.2. Fuel Cells.- 5. Batteries with ?-Alumina Electrolytes.- 5.1. Sodium-Sulfur Battery.- 5.2. Other Systems Using ?-Alumina.- 6. Solid State Ionics.- 6.1. General.- 6.2. Energy Conversion Devices.- 6.3. Other Devices.- 6.4. Advantages and Limitations.- References.- 7. Fabrication.- 1. Introduction.- 2. Single Crystals.- 2.1. Stabilized Zirconia.- 2.2. Thoria.- 2.3. Calcium Fluoride.- 2.4. ?-Alumina.- 2.5. AgI-Type Compounds.- 3. Polycrystalline Materials.- 3.1. Zirconia-Base Materials.- 3.2. Thoria-Base Materials.- 3.3. ?-Alumina.- 3.4. AgI-Type Electrolytes.- 4. Electrodes.- 4.1. Oxygen Ion Conductors.- 4.2. ?-Alumina.- 4.3. Fluorides.- 4.4. Silver Ion Conductors.- 5. Joining of Materials.- 6. Conclusions.- References.