Transport in dispersed ionic conductors: Effect of insulating particle size

Abstract

Abstract Dispersed ionic conductors are random mixtures of a solid salt, e.g. AgI, LiI, with fine particles of an insulating second phase, like Al2O3 or SiO2. These composites can show a dramatic increase in ionic conductivity compared to the pure homogeneous system. Generally, this observation is attributed to an increased conductivity along the internal interface between the conducting salt and the insulating material. In this work a three-component random resistor network (RRN) model for dispersed ionic conductors is reviewed. In the model, the ionic conductor is represented by normally conducting bonds, the insulating material by non-conducting bonds and the interface between the two phases by highly conducting bonds. A special feature of the model is the existence of two critical concentrations of the insulating phase, p′c and p″c , for interface percolation and bulk conduction, respectively, where critical transport properties corresponding to conductor/superconductor and conductor/insulator network...