Review Lecture - Fast ionic conduction in solid

Source abstract

Abstract Four classes of solid ionic conductors may be distinguished: (a) ion exchangers, (b) electrolytes, (c) electrodes, and (d) chemical stores. Each has important applications with different fabrication requirements. Fast ion transport is required in electric-power applications, and various strategies are discussed for power batteries. The design of new materials begins with a theoretical model for ionic transport; the situation in stoichiometric compounds is compared with that in doped compounds, and electrolytes are contrasted with mixed ionic-electronic conductors. The most significant parameters for the synthetic chemist are the factors that govern the activation enthalpy ∆Hm for diffusion, the concentration c of mobile carriers, and the temperature Tt for any phase transition from a normal to a fast ionic conductor. Strategies for decreasing ∆Hm and increasing c prove to be ion-specific, and the most successful strategies for each mobile ion are presented. The origin of a Tt in stoichiometric com­pounds and the distinction between smooth and first-order transitions are also considered.