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 X 10(-6) cm(2)/s at 21 degrees C, indicating that the plasticized polymer electrolytes behaved as a pure organic solution of plasticizer.