MIXED ETHER ELECTROLYTES FOR SECONDARY LITHIUM BATTERIES WITH IMPROVED LOW-TEMPERATURE PERFORMANCE

Tetrahydrofuran (THF): 2-methyl-tetrahydrofuran (2Me-THF)/LiAsF//6 mixed solutions, despite their lower conductivity, have allowed significantly better low temperature performance in Li/TiS//2 cells than have THF/LiAsF//6. **1**3C NMR data suggest that this may be related to the structurally disordered Li**4-solvates that exist in the mixed ether solutions. High cycling efficiencies for the Li electrode in THF:2Me-THF/LiAsF//6 solutions have been achieved by the use of 2Me-F as an additive. A 5 Ah capacity Li/TiS//2 cell has been cycled more than 100 times at 100% depth-of-discharge, with the cell capacity remaining at over 3 Ah at the 100th cycle.