In this paper, a geometric model for describing the effective ionic conductivity in a composite solid electrolyte is analysed. The model makes use of insulating particles that are coated with a highly ionically conducting phase and embedded in an ionically conducting matrix. Using a straightforward Maxwell type analysis we derive expressions for the effective ionic conductivity and diffusivity in the composite. It is shown by a Monte Carlo method that at low volume fractions of insulating phase this Maxwell analysis provides much better agreement than previous descriptions.
Diffusion in Materials - DIMAT2004. (Krakow, Poland 18 - 23 July 2004)