A mesoscopic model for the effective electrical conductivity of composite polymeric electrolytes

The effective quasistatic conductivity of composite polymeric electrolytes is studied in terms of a hard-core-penetrable-layer model. Used to incorporate the interface phenomena (such as amorphization of the polymer matrix around filler particles, stiffening effect by those on the amorphous phase, irregularities of the filler grains' surfaces, etc.), the layers are assumed to be electrically inhomogeneous, consisting of a finite or infinite number of concentric uniform shells. The rules of dominance, imposed on the overlapping regions, are equivalent to the requirement that the local electric properties in the system be determined by the distance from the point of interest to the nearest particle's center. The desired conductivity is calculated using our original many-particle (compact-group) approach which, however, avoids an in-depth elaboration of polarization and correlation processes. The result is expressed through the electrical and geometrical parameters of the constituents. Contrasting it with experiment reveals that the theory adequately describes the effective conductivity as a function of the filler concentration and temperature for a number of polymeric composites based on poly(ethylene oxide) or oxymethylene-linked poly(ethylene oxide) and is more flexible in comparison with other theories. (C) 2019 Elsevier B.V. All rights reserved.