Percolation concepts in solid state ionics

Structural disorder is an inherent property of solid materials, which can support 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 ionic conductors, which show conductance properties that can be related to random electrical networks, (ii) ion-doped network glasses, whose concentration-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 theory. (C) 1999 Elsevier Science B.V. All rights reserved.