▎ 摘　　要

NOVELTY - Cyanophosphite additive (I) and/or (II) is new. USE - Cyanophosphite additive used in lithium-ion battery (claimed). ADVANTAGE - The cyanophosphite additive improves the coulombic efficiency of the first cycle, its phosphorous acid and CN functional groups dissolve in the electrolyte after delithiation, participate in the formation of the SEI film, inhibits the decomposition of the electrolyte, and improves the high-temperature cycle performance of the battery. The phosphite organic lithium supplementation agent has high water and oxygen stability, which prevents harsh use and storage conditions. DETAILED DESCRIPTION - Cyanophosphite additive of formula (I) and/or (II) is new. R1=cyano, cyanoethyl, substituted or substituted 1-12C alkyl, substituted, or unsubstituted 6-26C aryl group, substituted or unsubstituted 6-22C aryl heteroyl group. An INDEPENDENT CLAIM is included for a lithium ion battery, which comprises positive pole, negative pole and electrolytic solution. The positive electrode includes the cyano-containing phosphite additive.