Electrochemical properties of lithium salt-poly(ethylene oxide)ethylene carbonate polymer electrolyte and discharge characteristics of Li/MnO2

Lithium salt-poly(ethylene oxide) polymer (PEG) electrolyte was prepared by solvent casting method. Ethylene carbonate (EC) was added to improve the ionic conductivity of the polymer electrolytes. The ionic conductivity of polymer electrolytes increased from 1.8 x 10(-7) S cm(-1) to 2.7 x 10(-5) S cm-L at 30 degrees C when the weight ratio of EC and PEO increased from 0 to 0.8. The activation energy of ionic conductivity obtained from log sigma vs. 1/T plot was 26.1 kJ mol(-1) when the EC/PEO weight ratio and [O]/[Li+] molar ratio were 0.8 and 25, respectively. The cyclic voltammetry results indicated that increasing the temperature resulted in the decrease of the peak potential difference of stripping of Li and deposition of Li+ (Delta E(p)). The discharge characteristic of lithium-manganese cell was significantly affected by the polymer electrolyte complexes, discharge temperature and current density.