Optimization of Cycling Behavior of Lithium Ion Cells at 60°C by Additives for Electrolytes Based on Lithium bis(1,2-oxalato(2-)-O,O´) borate

We investigated 13 additives well known from literature and studied their effect on the performance of lithium ion cells comprised of electrolytes based on lithium bis[1,2-oxalato(2-)-O,O ] borate. The additives can be attributed to three classes including chemically modified solvents, metal salts, and oligoethers. In contrast to similar studies in literature, where often only a single additive was investigated, the effect of 13 additives was studied under the same conditions at cells cycled up to 500 times at 60°C in a thermostat. The internal resistance of the cells and the charge capacity of cells are reported. Whereas tetra ethylene glycol dimethyl ether showed the best performance, increasing the lifetime of cells by a factor of five and doubling the cell capacity after 500 cycles other additives did show no effect or even deteriorated the cell performance.