Model studies of diffusion in glassy and polymer ion conductors

Ion-conducting glasses and polymer systems show several characteristic peculiarities in their composition-dependent diffusion properties and in their dynamic response. First we give a brief review of the current understanding of the ion dynamics in network glasses in terms of stochastic theories. Secondly, a model for PEO(polyethylene-oxide)-based polymer electrolytes is described. The equation of state is calculated from the quasichemical approximation. Using this information together with Monte Carlo simulations of diffusion at constant volume, we obtain constant-pressure results for polymer chain and ion diffusion as a function of ion concentration. This theory allows us to make comparison with experiments which are carried out at constant pressure.