Non-aqueous electrolyte of lithium ion battery and lithium ion battery

Abstract

The invention proposes a non-aqueous electrolyte of a lithium ion battery and the lithium ion battery containing the non-aqueous electrolyte. The non-aqueous electrolyte of the lithium ion battery comprises a lithium salt, a non-aqueous solvent and a first additive and is characterized in that the first additive is phosphorothioate having a structure shown as in formula (1), wherein R1 and R2 are respectively selected from one of -(CH<2>)<n>-CH<3>, -(CH<2>)<n>-CF<3>, -NO<2> and -SO<3>, n is an integer from 0 to 4, R3 until R7 are respectively selected from one of -CN, -F, -Cl, -Br, -CF<3>, -NO<3> and -H, and at least one of R3 until R7 is one of -CN, -F, -Cl, -Br, -CF3 and -NO<3>. The first additive disclosed by the invention is added into the non-aqueous electrolyte of the lithium ion battery, and thus, the electrolyte can be prevented from generating side reaction on a surface of a battery positive electrode to cause degradation; and the battery obtained through preparation has relatively high charge-discharge performance, the capacity retention ratio is high after circulation, and the battery is small in deformation before and after circulation and is long in service lifetime.

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 oxidize and decompose and the bat...

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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 oxidize and decompose and the battery cannot 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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