ELECTROLYTE FUNCTIONAL ADDITIVE FOR LITHIUM ION BATTERY, LITHIUM ION BATTERY ELECTROLYTE AND LITHIUM ION BATTERY

摘要

An electrolyte functional additive for a lithium ion battery, a lithium ion battery electrolyte and a lithium ion battery. The functional additive comprises in parts by weight: 0.1-0.5 parts of lithium tetrafluoroborate, 0.3-1.5 parts of lithium bisoxalatoborate and 0.2-2 parts of vinylene carbonate. The functional additive ensures that a dense and stable SEI film is formed on the surface of a negative electrode, which improves the high-temperature storage performance and high-temperature cycle performance of a battery. The lithium tetrafluoroborate and the lithium bisoxalatoborate form an intermediate product, i.e. lithium difluoroborate, and said substance can prevent the catalytic oxidation of the electrolyte on the surface of a positive electrode, and can also reduce the oxidative decomposition of the electrolyte so as to improve the cycle performance of the battery. The lithium ion battery electrolyte with the functional additive simultaneously contains the lithium tetrafluoroborate, lithium bisoxalatoborate and lithium difluoroborate during use, and can still maintain high electrical performance in low or high-temperature environments by taking advantage of the respective advantages thereof.