Conductivity measurements were performed on composites involving a Cu+-ion conductor and a dispersed insulating oxide such as titania or alumina. A numerical model which assumed a simple topology, and an increased conductivity in narrow regions near to the heterophase boundaries, provided a satisfactory explanation of the experimental results; especially with regard to the concentration dependence of the conductivity. A bell-shaped curve, with a concave initial characteristic, was obtained for incomplete wetting between CuBr and titania. In the case of strong wetting (CuBr/alumina), a linear relationship was observed between conductivity and volume fraction over a certain range.

Electrical Conductivity of Model Composites of an Ionic Conductor (CuBr) and an Insulator (TiO2, Al2O3) - Experiments and Percolation-Type Model. P.Knauth, J.M.Debierre, G.Albinet: Solid State Ionics, 1999, 121[1-4], 101-6