Microelectrode investigation of the lithium redox behavior in plasticized polymer electrolytes

The lithium redox behavior in plasticized polymer electrolytes has been studied by microelectrode technique with the advantage in decreasing the iR effect of solution resistance. PAN (polyacrylonitrile)-, PVdF (poly(vinylidene fluoride))- and PVC (poly(vinyl chloride))-based plasticized electrolytes showed ionic conductivities ranging from 10−4 to 10−3 S/cm at ambient temperature. By applying high scan rate (-V/s), the aggravating effect of the electrolyte decomposition with freshly deposited lithium was suppressed, and the reliable kinetic parameters of the lithium deposition/dissolution and the diffusion coefficient of lithium ion were evaluated for PAN- and PVdF-based electrolytes. The obtained diffusion coefficient for the PAN-based electrolyte was 1.50 × 10−6 cm2/s at 21 °C, indicating that the plasticized polymer electrolytes behaved as a pure organic solution of plasticizer.