Stochastic model of lithium ion conduction in poly(ethylene oxide)

We develop, analyze, and simulate a physical model of Li(+)-ion conduction inside polyethylene oxide (PEO) helical tubes, which are the solvent of LiI salt. The current is due to diffusion and electric interactions with a permanent external field, the PEO charges, and ion-ion interactions. Potential barriers are created in the PEO by loops in structure. We calculate the energy of configurations of one or two lithium ions in the loop and derive an explicit expression for the activation energy. We use Kramers' formula to calculate the conductivity as function of mechanical stretching, which lowers the barrier and causes an exponential rise in the output conductivity.