Percolation in composites

Many properties of composite materials such as diffusion, electrical conduction, dielectric response as well as elasticity, are intimately related to the geometrical arrangement of the constitutive phases, including the geometry of the respective interfaces. Percolation theory, whose objective is to characterize the connectivity properties in random geometries and to explore them with respect to physical processes, thus provides a natural frame for the theoretical description of random composites. This article explains basic concepts of static percolation theory and percolative transport, which subsequently are applied to specific experiments on heterogeneous ionic conductors.