SOLVENT MATERIALS FOR USE IN ELECTROLYTE SOLUTIONS OF RECHARGEABLE CELLS WITH LITHIUM METAL ANODES

Abstract

A rechargeable cell with a lithium metal anode (lithium metal cell) is attractive because theoretically it has a high energy density. The problems with lithium metal cells are their short cycle life and poor safety resulting from their low cycling efficiency and the high chemical reactivity of lithium. One of the most important factors is the selection of the electrolyte màterials. In this paper, we examine 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. The goals are to improve the cycle life of the cell while ensuring its safety and controlling its cost. The cell performance examined here includes cell capacity and charge-discharge cycle life. We also carried out a heating abuse test at 130°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 our overall results on cycle life, capacity, safety and cost.