Linear and nonlinear conductive spectra of ion-conducting polymers

The linear and nonlinear complex conductivities have been measured as a function of frequency for the polyethylene oxide modified by the addition of SiO₂, or doped with LiClO₄. The observed spectra exhibit marked conductive relaxation, suggesting the existence of different conduction processes in the low-frequency regions. It was found that combinations of the linear and nonlinear conductivities as given by the dynamic percolation theory allow estimates of a hopping distance without any additional assumptions. It was also suggested that the elementary process of the ion transport in the ion-conducting polymers was caused by ion hopping between available sites, and therefore, the typical size of a cluster of available sites is about 4 nm