New Li-ion electrolytes for low temperature applications

Ethyl acetate and methyl butyrate have been tested as new solvents for Li-i on liquid electrolytes. Specific ternary mixtures have been investigated, c ontaining cyclic carbonate and linear carbonate solvents in addition to the esters. Thanks to their high conductivities, these electrolytes make it po ssible to obtain very good performances below -30 degreesC, in different Li CoO2//graphite cells. Moreover, these electrolyte compositions do not affec t cyclability, charge retention of safety of the LiCoO2 cells, behaving as pure carbonate electrolytes. (C) 2001 Elsevier Science B.V. All rights rese rved.