INFLUENCE OF THE COMPOSITION OF TERNARY MIXED-SOLVENT ELECTROLYTES ONTHE 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 fa bricating an AA-size prototype cell has been studied. The influence of the composition of ternary mixed solvent electrolytes comprising ethy lene carbonate (EC), propylene carbonate (PC) and 2-methyltetrahydrofu ran (2MeTHF) on the properties of AA-size Li/a-V2O5-P2O5 cells is exam ined. The goals are to improve the cycle life of the cell while ensuri ng its safety and controlling its cost. The electrolyte composition is varied by changing the solvent mixing ratio, and the lithium salt con centration, and by using different kinds of solute, The cell performan ce examined includes cathode utilization (cell capacity) during low te mperature operation, and charge-discharge cycle life. Heating abuse te sts 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, sa fety and cost.