ADDITIVES FOR HIGH VOLTAGE LITHIUM ION BATTERIES

This invention relates to an electrolyte composition for a lithium ion battery comprising a lithium salt in a non-aqueous solvent containing an additive comprising a compound of formula RSiOP(O)F; wherein each R independently is a hydrocarbyl group; and n is 0 or 1; and wherein the additive is substantially free from (RSiO)P(O)and (RSiO)P(O)F. Electrochemical cells and batteries also are described.