Electrolyte additive, lithium battery electrolyte and lithium ion battery

Abstract

The invention relates to an electrolyte additive, an electrolyte and a lithium battery, and belongs to the technical field of lithium batteries. The electrolyte additive comprises at least one of thecompounds shown in the structural formula I: a formula which is as shown in the specification, wherein R in the structural formula I is one of a fluorine group, a phenyl group, an alkyl group, and analkenyl group, wherein n is an integer of 1 to 5. According to the electrolyte additive, the electrolyte additive is subjected to a decomposition reaction in the electrolyte, and the obtained productgenerates a protective film on the surface of a positive electrode, so that a passivation effect is achieved, dissolution of a metal element in a positive electrode material and the collapse of the positive electrode material structure are inhibited, the electrochemical stability window of the electrolyte is improved, the working voltage range of the electrolyte is widened, and the cycling efficiency of the battery under a high voltage (for example 4.2-5.0V) can be effectively improved.

Description

technical field [0001] The invention relates to an electrolyte additive, a lithium battery electrolyte and a lithium ion battery, belonging to the technical field of lithium batteries. Background technique [0002] Portable electronic devices such as laptops, mobile phones, portable audio, and electric vehicles all require lithium-ion batteries with higher energy density, so that they can be lighter and smaller while having stronger battery life. In order to obtain a lithium-ion battery with high energy density, a method of using a negative electrode material with a large capacity, a method of using a high-potential positive electrode, etc. have been developed. Improving the working voltage of lithium-ion batteries is an effective way to improve their energy density and rate performance. The working voltage of existing general lithium-ion batteries is 3.5V-4.2V. The main factor that currently limits the working voltage of lithium-ion batteries is The electrochemical stabili...

AI Technical Summary

Problems solved by technology

Improving the working voltage of lithium-ion batteries is an effective way to improve their energy density and rate performance. The working voltage of existing general lithium-ion batteries is 3.5V-4.2V. The main factor that currently limits the working voltage of lithium-ion batteries is The electrochemical stability window of the carbonate electrolyte used in commercial applications is relatively low. When the voltage reaches about 4.5V, an oxidative decomposition reaction will occur, which greatly reduces the cycle performance and safety performance of lithium-ion batteries.

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