Separating the effects of Tg and solvent polarity in polymer electrolytes

Solid (solvent-free) polymer electrolytes are promising alternatives to conventional liquid counterparts in Li-ion batteries. By separating the effect of T_g and the effect of solvent polarity in our molecular dynamics simulations, we show that the maximum in the diffusion coefficient of Li+ with respect to the dielectric constant of polymer-solvent ε_p is due to transitions in the transport mechanism. The balanced interactions between Li-ion with TSFI and PEO at an intermediate value of ε_p leads to the fast ion conduction.