A kind of lithium-ion battery non-aqueous electrolyte and lithium-ion battery

Abstract

The present invention proposes a lithium-ion battery non-aqueous electrolyte and a lithium-ion battery containing the non-aqueous electrolyte. The lithium-ion battery non-aqueous electrolyte includes a lithium salt, a non-aqueous solvent and a first additive, and is characterized by: The first additive is a sulfur phosphate with a structure shown in formula (1): Formula (1); where, R 1 ,R 2 Each independently selected from -(CH 2 )n‑CH 3 ,‑(CH 2 )n‑CF 3 ,‑NO 2 ,‑SO 3 One of them, n is an integer from 0 to 4, R 3 ~R 7 Each is independently selected from one of -CN, -F, -Cl, -Br, -CF3, -NO3, -H, and R 3 ~R 7 At least one of them is one of -CN, -F, -Cl, -Br, -CF3 and -NO3. By adding the first additive of the present invention to the non-aqueous electrolyte of the lithium ion battery, the present invention can prevent the electrolyte from deteriorating due to side reactions on the surface of the positive electrode of the battery. The prepared battery not only has higher charge and discharge performance, but also The capacity retention rate after cycling is high, the battery deformation is small before and after cycling, and the battery life is long.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, in particular to a nonaqueous electrolytic solution for a lithium ion battery and a lithium ion battery containing the nonaqueous electrolytic solution. Background technique [0002] In recent years, the secondary lithium ion battery of high energy density has become the object of people's attention. Therefore, people have also noticed that some new active materials that can be used as secondary lithium batteries, such as the prior art once disclosed a platform of about 4.7 V's high-voltage cathode material LiNi0.5Mn1.5O4, the increase of its working voltage directly improves the power of the battery as a whole, which has great practical significance in application. However, at this stage, most lithium battery electrolyte systems It can only be used stably at a voltage of 4.5v and below. When the working voltage reaches above 4.5v, the electrolyte system will be oxidized and decomposed and th...

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Problems solved by technology

[0002] In recent years, the secondary lithium ion battery of high energy density has become the object of people's attention. Therefore, people have also noticed that some new active materials that can be used as secondary lithium batteries, such as the prior art once disclosed a platform of about 4.7 V's high-voltage cathode material LiNi0.5Mn1.5O4, the increase of its working voltage directly improves the power of the battery as a whole, which has great practical significance in application. However, at this stage, most lithium battery electrolyte systems It can only be used stably at a voltage of 4.5v and below. When the working voltage reaches above 4.5v, the electrolyte system will be oxidized and decomposed and the battery will not work normally. Therefore, the existing electrolyte seriously hinders the development of high-voltage positive electrode materials. widely used

[0003] There are usually two solutions to this defect in the prior art. One is to find a new electrolyte solvent, such as Chinese patent 200510012077.1 which discloses a halogenated cyclic sulfite high-voltage electrolyte solvent; the other is to add A certain amount of additives is used to form a protective film on the surface of the positive or negative electrodes. For example, Chinese patent 01121439.2 discloses adding thiophene to the electrolyte to improve the cycle life of the battery; but the above two solutions have no substantial effect on the cycle performance of lithium-ion batteries Improvement on

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