화학공학소재연구정보센터
Electrochimica Acta, Vol.42, No.1, 119-125, 1997
Influence of Electrolyte-Composition of Ethylene Carbonate/Propylene Carbonate Mixed Systems on the Properties of Rechargeable Li/Amorphous V2O5-P2O5 Cells
This paper examines the influence of electrolyte composition (solvent mixing ratio) of LiAsF6-ethylene carbonate (EC)/propylene carbonate (PC) mixed solvent electrolytes on the rate capability and the charge-discharge cycling life of AA-type lithium (Li) metal/amorphous (a-)V2O5-P2O5 (95:5 in molar ratio) cells. In addition, fundamental abuse tests were carried out on the Li/a-V2O5-P2O5 cells consisting of a heating test at 130 degrees C and an external short circuit test at 25 degrees C. As a result, the following three facts were determined. First, the rate capability does not differ greatly with a change in electrolyte composition. Second, the cycle life reaches its maximum value at an EC/PC volume mixing ratio of 1:9, although the Li cycling efficiency obtained from the Li half-cell test increases with an increase in EC content in the EC/PC mixed system. This is the result of an interaction between the cathode and electrolyte leading to the formation of film containing vanadium on the Li anode surface different from that usually formed in Li metal batteries by the reaction between the electrolyte and Li. Third, fundamental cell safety is ensured by the above abuse tests. The relatively better results of the heating tests for the Li/a-V2O5-P2O5 cells are because of the enhancement of the thermal stability of the Li anode with the special surface film in the Li/a-V2O5-P2O5 cell system.