Percolation concepts in solid state ionics

Structural disorder is an inherent property of solid materials, which can s upport a macroscopic ionic current. Many transport phenomena in these solid ionic conductors appear to be related to concepts from percolation theory. We demonstrate this for three classes of materials, namely (i) dispersed i onic conductors, which show conductance properties that can be related to r andom electrical networks, (ii) ion-doped network glasses, whose concentrat ion-dependent diffusion properties are accessible by critical path analysis , and (iii) polymer ionic conductors. For the latter we discuss Monte Carlo simulations which indicate the applicability of dynamic bond percolation t heory. (C) 1999 Elsevier Science B.V. All rights reserved.