Journal of Applied Electrochemistry, Vol.27, No.8, 902-907, 1997
Influence of the Composition of Ternary Mixed-Solvent Electrolytes on the Properties of Rechargeable Lithium Cells
A cell system consisting of an amorphous (a-)V2O5-P2O5 (95:5 in molar ratio) cathode, a lithium metal anode and an organic electrolyte by fabricating an AA-size prototype cell has been studied. The influence of the composition of ternary mixed solvent electrolytes comprising ethylene carbonate (EC), propylene carbonate (PC) and 2-methyltetrahydrofuran (2MeTHF) on the properties of AA-size Li/a-V2O5-P2O5 cells is examined. The goals are to improve the cycle life of the cell while ensuring its safety and controlling its cost. The electrolyte composition is varied by changing the solvent mixing ratio, and the lithium salt concentration, and by using different kinds of solute, The cell performance examined includes cathode utilization (cell capacity) during low temperature operation, and charge-discharge cycle life. Heating abuse tests were also carried out at 130 degrees C on the Li/a-V2O5-P2O5 cells. The best electrolyte composition was found to be 1.15m LiAsF6-EC/PC/2MeTHF (15:70:15) from the overall results on cycle life, capacity, safety and cost.