Poly(methylmethacrylate) - magnesium triflate gel polymer electrolyte for solid state magnesium battery application

A gel polymer electrolyte (GPE) film of poly(methylmethacrylate) and magnesium triflate is studied in view of its potential application in a solid state rechargeable magnesium battery. Experimental data of a.c. impedance and cyclic voltammetric studies of symmetrical cells made of blocking and non-blocking electrodes, and also data of charge/discharge cycles of Mg/GPE/MnO2 cells are reported. The composition of the GPE is optimized in view of a minimum quantity of the liquid components (propylene carbonate and ethylene carbonate) required for the gel formation and a maximum conductivity. Specific conductivity (sigma) of the GPE of optimum composition is (4.2 +/- 0.45) x 10(-4) S cm(-1) at 20 degreesC. The sigma values follow the Arrhenius equation and the activation energy for GPE of optimum composition is 0.038 eV. The effects of temperature and ageing on Mg/GPE interface are studied. Discharge capacity of about 90 mAh g(-1) of MnO2. is obtained during the discharge of Mg/GPE/MnO2 cells. On repeated charge/discharge cycling of the cell, the discharge capacity decreases to about 70 mAh g(-1). The cycle-life is limited by the problems associated with passivation of the Mg surface. (C) 2002 Elsevier Science Ltd. All rights reserved.