Solid electrolytes or superionics are materials which exhibit exceptionally high values of ionic conductivity due to the rapid diffusion of one ionic species through a lattice formed by immobile counterions. Originally studied by Faraday in the 1830s, and for many years considered little more than scientific curiosities, ionically conducting solids are now a widely studied class of materials with important technological applications within solid state batteries, gas sensors and fuel cells.


This book aims to provide an introduction to solid electrolytes and their historical development. A detailed summary of the major families of superionic compounds will be presented, with particular emphasis on the most important examples. An assessment of our current understanding of the relationship between the crystal structure of superionics and their bulk conduction processes will be given, permitting a discussion of the factors which promote rapid ionic motion within solids. These more 'fundamental' research issues will be complemented by a discussion of the technological applications of ionically conducting solids, their current limitations and future prospects.