Non-aqueous electrolyte and lithium-ion battery

Abstract

The invention provides a nonaqueous electrolyte solution and a lithium ion battery. The nonaqueous electrolyte solution includes: a lithium salt, a nonaqueous organic solvent and an additive. The additive includes a heterocyclic compound with a structure shown as formula I and phosphoric acid cyclic anhydride with a structure shown as formula II. In the formula I, X is selected from one of S, O and NH, R1 and R2 are independently selected from any one of H, saturated alkyl with 1-10 carbon atoms, unsaturated alkyl with 1-10 carbon atoms and alkyl, or R1 and R2 are interconnected into a ring, and the H on the saturated alkyl and unsaturated alkyl can be partially or completely replaced by halogen, nitro, cyano, carboxyl, and sulfonyl. In the formula II, R3, R4 and R5 are independently selected from H, saturated alkyl with 1-20 carbon atoms, unsaturated alkyl with 1-20 carbon atoms, or a group with 6-18 carbon atoms and at least one benzene ring. The nonaqueous electrolyte solution provided by the invention can improve the rate charging performance of the lithium ion battery without affecting the storage performance and cycle performance of the lithium ion battery. (formula I and formula II).

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery manufacturing, in particular to a non-aqueous electrolyte and a lithium-ion battery. Background technique [0002] As a working power source for electronic products, lithium-ion batteries have the characteristics of high energy density, no memory effect, and high working voltage, and are gradually replacing traditional Ni-Cd batteries and MH-Ni batteries. However, with the expansion of market demand for electronic products and the development of power and energy storage equipment, people's requirements for the energy density of lithium-ion batteries continue to increase, and the development of lithium-ion batteries with high energy density has become a top priority. [0003] In order to increase the energy density of lithium-ion batteries, developing high-voltage lithium-ion batteries is one of the effective methods. At present, lithium-ion batteries with an operating voltage above 4....

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Problems solved by technology

However, when the heterocyclic compound undergoes electropolymerization, it will generate hydrogen ions, and the excess hydrogen ions will be combined with LiFP 6 Continuously react with the SEI film generated by the negative electrode, thereby affecting the storage performance and cycle performance of lithium-ion batteries

[0005] The Chinese patent technical document CN103779607A published on May 7, 2014 discloses that cyclic phosphoric anhydride can form a polymer film on the surface of the positive electrode material to enhance the stability of the positive electrode interface, but the passivation film formed by the cyclic phosphoric anhydride is relatively thick, and its The product is a phosphate polymer, and a small amount of water in the lithium-ion battery will break the molecular chain of the phosphate polymer

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