Phosphite lithium ion battery electrolyte additive and application thereof

Abstract

The invention discloses a phosphite ester lithium ion battery electrolyte additive. The structural general formula of the phosphite ester lithium ion battery electrolyte additive is as shown in a formula 1, wherein R is one of the following groups: silyl, a silyl group containing a cyano group, a linear or non-linear alkyl group having 1-6 carbon atoms, a linear or non-linear unsaturated hydrocarbon group having 1-6 carbon atoms, an acyloxy group, and sulfonyl. The invention also provides a preparation method of the additive and an application of the additive in a lithium ion battery electrolyte. When the additive provided by the invention is applied to the lithium battery electrolyte, combustion or explosion of an organic solvent can be effectively prevented, the thermal stability of the electrolyte is improved, a positive electrode / electrolyte interface is stabilized, the electrochemical property is improved, the positive electrode stability is improved, the stability and safety of battery circulation are improved, and meanwhile, the charge / discharge circulation efficiency of a lithium ion battery is improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a phosphite lithium ion battery electrolyte additive and its application. Background technique [0002] Lithium-ion batteries have been widely used in portable electronic products such as mobile phones, notebook computers and small power-driven devices due to their advantages of high voltage, no memory effect, high specific energy, environmental protection and long life. However, in recent years, due to the safety issues caused by thermal runaway caused by batteries under abuse (thermal shock, overshoot, short circuit, etc.), especially in the application of large-capacity power sources such as electric vehicles, safety issues are particularly important. [0003] At present, most lithium-ion battery electrolytes are organic liquid electrolytes, which are composed of organic solvents and conductive lithium salts. Commonly used organic solvents are alkyl ...

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Problems solved by technology

Although the battery is equipped with a protection circuit, a safety valve, and a positive temperature coefficient thermistor (PTC), it cannot completely avoid the leakage, combustion or even explosion of these organic solvents.

[0004] In addition, when a lithium-ion battery is in a charged state, partial oxidation and decomposition will occur at the interface between the positive electrode material and the non-aqueous electrolyte, so the resulting decomposition products will hinder the original electrochemical reaction of the battery, resulting in a decrease in performance such as battery cycle characteristics.

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