Lithium battery electrolyte and application thereof in lithium ion battery

An electrolyte, lithium battery technology, applied in electrolyte, secondary battery, secondary battery repair/maintenance, etc., can solve the negative impact of increasing battery internal resistance, battery rate performance and low temperature performance, and the effect is not as good as fluorinated solvent electrolysis It can solve the problems of high temperature gas production, improve the stability of high voltage cycle, and broaden the environmental adaptability.

Pending Publication Date: 2021-09-07
CHINA AUTOMOTIVE BATTERY RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The polymers produced by these additives adhere to the electrode surface, which can improve the high-voltage cycle performance of the battery to a certain extent, but the effect is not as good as that of the fluorinated solvent electrolyte, and will increase the internal resistance of the battery, which will negatively affect the battery rate performance and low-temperature performance.

Method used

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  • Lithium battery electrolyte and application thereof in lithium ion battery
  • Lithium battery electrolyte and application thereof in lithium ion battery
  • Lithium battery electrolyte and application thereof in lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] 1. Preparation of lithium battery electrolyte

[0043] The preparation of the electrolyte in the examples is carried out in an argon glove box, and the moisture and oxygen content in the glove box are all controlled below 0.5ppm. Lithium hexafluorophosphate of ethyl ester and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (EMC:FEC:TFEA:F-EPE=50:25:15:10) (concentration 1.0M) and lithium difluorooxalate borate (0.1M) solution, adding mass ratios were 0.5% lithium difluorophosphate, 1% 1,3-propane sultone, 0.5% 1,3-(1 -propene) sultone, 0.5% adiponitrile, 0.1% 2-fluorobiphenyl and 0.5% bis(vinylsulfonyl)methane to make lithium battery electrolyte. After testing, the water in the electrolyte is <20ppm, and the free acid is <50ppm.

[0044] 2. Preparation of lithium ion battery

[0045] In the embodiment, a 2Ah battery is used, the lithium-rich pole piece is used as the positive electrode, the silicon-carbon pole piece is used as the negative pole, and the poly...

Embodiment 2

[0047] 1. Preparation of lithium battery electrolyte

[0048] The preparation of electrolyte in the embodiment is carried out in an argon glove box, and the moisture and oxygen content in the glove box are all controlled below 0.5ppm. (EMC: FEC: DFEA = 50: 25: 25) Lithium hexafluorophosphate (concentration 1.0M) and lithium bisfluorosulfonyl imide (0.1M) solution, add mass ratio of 0.5% lithium difluorophosphate, 1% 1 ,3-propane sultone, 0.5% 1,3-(1-propene) sultone, 0.5% adiponitrile, 0.2% cyclohexylbenzene and 0.5% N,N'-bis(vinylsulfonyl acetyl base) ethylenediamine to make lithium battery electrolyte. After testing, the water in the electrolyte is <20ppm, and the free acid is <50ppm.

[0049] 2. Preparation of lithium ion battery

[0050] In the embodiment, a 2Ah battery is used, the lithium-rich pole piece is used as the positive electrode, the silicon-carbon pole piece is used as the negative pole, and the polyolefin diaphragm and the lithium battery electrolyte prepar...

Embodiment 3

[0052] 1. Preparation of lithium battery electrolyte

[0053] The preparation of electrolyte in the embodiment is carried out in an argon glove box, and the moisture and oxygen content in the glove box are all controlled below 0.5ppm, to methyl ethyl carbonate, fluoroethylene carbonate and 2,2,2-trifluoroacetic acid In ethyl ester (EMC:FEC:TFEA=50:25:25) lithium hexafluorophosphate (1.0M), lithium difluorooxalate borate (0.5M) and lithium bisfluorosulfonyl imide (0.5M) solution, add mass ratio respectively 0.5% lithium difluorophosphate, 1% 1,3-propane sultone, 0.5% 1,3-(1-propene) sultone, 0.5% adiponitrile, 0.3% 2,5-dichlorothiophene and 0.8% bis(vinylsulfonyl)methane to make lithium battery electrolyte. After testing, the water in the electrolyte is <20ppm, and the free acid is <50ppm.

[0054] 2. Preparation of lithium ion battery

[0055] In the embodiment, a 2Ah battery is used, the lithium-rich pole piece is used as the positive electrode, the silicon-carbon pole pie...

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Abstract

The invention relates to the technical field of lithium ion battery materials, in particular to a lithium battery electrolyte and application thereof in a lithium ion battery. The lithium battery electrolyte comprises a lithium salt, an organic solvent and additives, wherein the lithium salt is selected from one or more of lithium hexafluorophosphate, lithium difluoro (oxalato) borate and lithium bis (fluorosulfonyl) imide, the organic solvent is carbonic ester and a fluorinated solvent, the additives comprise an additive I and an additive II, the additive I is a benzene derivative and a heteroaromatic compound, and the additive II is bis (vinyl sulfonyl) methane and a structural analogue thereof. The lithium battery electrolyte provided by the invention can form a surface film with high electronic conductivity and ionic conductivity on the surface of a lithium-rich positive electrode material. The problem of high-temperature gas production of a fluorinated solvent electrolyte can be solved while it is ensured that the high-voltage cycling stability of a lithium ion battery is improved, the lithium battery electrolyte has low-temperature discharge performance, and therefore, the environmental adaptability of the lithium-rich material is widened.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery materials, in particular to a lithium-ion battery electrolyte and its application in lithium-ion batteries. Background technique [0002] Both energy storage and electric vehicles put forward higher requirements on the energy density of lithium-ion batteries; among them, the energy density of positive electrode materials is the key link to limit the energy density of batteries, and the lithium-rich positive electrode material xLi 2 MnO 3 ·(1-x)LiMO 2 (0<x<1, M=Mn, Co, Ni) has become one of the most promising new cathode materials due to its high specific capacity, low cost, and environmental friendliness. However, the electrolyte is prone to side reactions with the surface of the cathode material under high voltage, resulting in a decrease in battery performance. These shortcomings limit the practical application of high specific capacity cathode materials. [0003] Due to its...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/0569H01M10/0567H01M10/0568H01M10/0525H01M10/42
CPCH01M10/0569H01M10/0567H01M10/0568H01M10/0525H01M10/4235H01M2300/0034H01M2300/0037Y02E60/10
Inventor 常增花任志敏张海燕王仁念刘丙学张强李彬杨嫚王建涛
Owner CHINA AUTOMOTIVE BATTERY RES INST CO LTD
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