Lithium ion battery non-aqueous electrolytic solution and lithium ion battery

Abstract

The invention discloses a lithium ion battery non-aqueous electrolytic solution, which comprises an electrolyte lithium salt, a non-aqueous organic solvent and a film-forming additive, wherein the film-forming additive comprises at least two of tetravinyl silane, tris (trimethylsilane) phosphate and a conventional additive. The invention also discloses a lithium ion battery containing the non-aqueous electrolytic solution of the lithium ion battery. According to the invention, the tetravinyl silane additive has a high HOMO energy level, and can form a passivation film (the oxygenolysis potential is 4.15 V vs Li / Li<+>) on a positive electrode interface prior to a solvent after battery capacity grading is finished, so that other components in the electrolytic solution are prevented from oxygenolysis on the positive electrode interface under high voltage, and the formed passivation film has better thermal stability; and the tris (trimethylsilane) phosphate has the characteristic of reducing the impedance of an interfacial film of the battery, and the combination of the high and low impedance additives can better improve the high and low temperature performance, the rate capability and the storage performance of the battery.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery non-aqueous electrolyte and a lithium ion battery. Background technique [0002] Lithium-ion batteries are widely used in 3C digital products, power tools, electric vehicles and other fields due to their advantages such as high working voltage, high energy density, long life and environmental friendliness. Especially in the 3C digital field, in recent years, the development trend of mobile electronic devices such as mobile power banks for smartphones is lighter and thinner, making lithium-ion batteries more and more popular. [0003] In order to increase the energy density of lithium-ion batteries, a common measure is to increase the charge cut-off voltage of the positive electrode material, such as the commercial lithium cobalt oxide lithium-ion battery voltage from 4.2V→4.35V→4.4V→4.45V→4.48V→4.5V . [0004] However, there are certain defec...

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Problems solved by technology

The disadvantage is: through experiments, it is found that the addition of tetravinylsilane can also form an anodic oxidation film, but the resistance of the formed passivation film is too large, which will affect the electrochemical performance of the battery

Therefore, it is necessary to develop a new type of lithium-ion battery electrolyte, which can not only give full play to the advantages of tetravinylsilane additives, but also effectively solve the problem that the resistance of the passivation film formed by adding tetravinylsilane to the positive electrode oxidation film is too large, which affects the lithium-ion battery. The issue of electrochemical performance of the secondary battery

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