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CN-122000465-A - Wide-temperature electrolyte and lithium ion battery

CN122000465ACN 122000465 ACN122000465 ACN 122000465ACN-122000465-A

Abstract

In order to solve the problem that commercial lithium ion battery electrolyte cannot achieve both high-temperature performance and low-temperature performance, the invention provides a wide-temperature electrolyte which comprises a nonaqueous organic solvent, lithium salt and an additive, wherein the additive comprises an additive A, and the structural formula of the additive A is as follows: Wherein R 1 、R 2 is each independently selected from nitro, substituted or unsubstituted hydrocarbyl, cyano, halogen, or hydrogen, at least one of the R 1 、R 2 is not hydrogen, and when one of the R 1 、R 2 is hydrogen, the other is nitro. By adding the additive A into the electrolyte, the battery has good high-temperature and low-temperature performances, and the wide-temperature performance of the electrolyte is more excellent, so that the use scene of the lithium ion battery is widened.

Inventors

  • WANG ZHITAO
  • XU KAICHEN
  • GU MINGYAO
  • YU LINPO
  • GAN CHAOLUN

Assignees

  • 张家港市国泰华荣化工新材料有限公司

Dates

Publication Date
20260508
Application Date
20241107

Claims (11)

  1. 1. The wide-temperature electrolyte comprises a nonaqueous organic solvent, lithium salt and an additive, and is characterized in that the additive comprises an additive A, and the structural formula of the additive A is as follows: Wherein R 1 、R 2 is each independently selected from nitro, substituted or unsubstituted hydrocarbyl, cyano, halogen, or hydrogen, at least one of the R 1 、R 2 is not hydrogen, and when one of the R 1 、R 2 is hydrogen, the other is nitro.
  2. 2. The wide temperature range electrolyte according to claim 1, wherein R 1 、R 2 is independently selected from a nitro group, a substituted or unsubstituted hydrocarbon group having 1 to 6 carbon atoms, or hydrogen, and a substituent of the hydrocarbon group is halogen.
  3. 3. The wide temperature range electrolyte according to claim 2, wherein R 1 is a nitro group and R 2 is selected from a nitro group, hydrogen, an alkyl group having 1 to6 carbon atoms, or a phenyl group R 1 、R 2 is independently selected from alkyl with 1-3 carbon atoms or halogen.
  4. 4. The broad temperature electrolyte of claim 3 wherein additive A is selected from one or more of the group consisting of:
  5. 5. The wide temperature range electrolyte according to claim 1 to 4, wherein at least one of R 1 、R 2 is a nitro group, and when only one is a nitro group, the other is selected from alkyl groups having 1 to 3 carbon atoms.
  6. 6. The wide temperature range electrolyte solution according to claim 1, wherein the additive A accounts for 0.1-5% of the total mass of the electrolyte solution.
  7. 7. The broad temperature electrolyte as in claim 1, wherein the additive further comprises an additive B selected from one or more of lithium difluorophosphate, lithium difluorodioxalate phosphate, fluoroethylene carbonate.
  8. 8. The wide temperature range electrolyte solution according to claim 7, wherein the additive B accounts for 1-10% of the total mass of the electrolyte solution.
  9. 9. The broad temperature electrolyte as claimed in claim 1, wherein the lithium salt is lithium hexafluorophosphate and lithium difluorosulfonimide, the molar content of the lithium hexafluorophosphate in the electrolyte is greater than the molar content of the lithium difluorosulfonimide in the electrolyte, and/or, The organic solvent includes cyclic carbonates, chain carbonates and chain carboxylates.
  10. 10. The broad temperature electrolyte as claimed in claim 9, wherein the concentration of the lithium hexafluorophosphate in the electrolyte is 0.8-1.5M, and/or, The concentration of the lithium bis (fluorosulfonyl) imide in the electrolyte is 0.01-0.5M, and/or, The cyclic carbonate is selected from one or more of ethylene carbonate and propylene carbonate, and/or, The chain carbonate is methyl ethyl carbonate, and/or, The chain carboxylic acid ester is selected from one or more of ethyl propionate and propyl propionate, and/or, The mass ratio of the cyclic carbonate to the chain carboxylate is (15-50)/(5-20)/(30-80).
  11. 11. A lithium ion battery comprising a positive electrode, a separator and a negative electrode, wherein the lithium ion battery further comprises the electrolyte as set forth in any one of claims 1 to 10.

Description

Wide-temperature electrolyte and lithium ion battery Technical Field The invention relates to the technical field of lithium ion batteries, in particular to a wide-temperature electrolyte and a lithium ion battery. Background This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section. The lithium ion battery has the advantages of high energy density, high power density, long cycle life and the like, and has been widely applied to the fields of consumer electronics products, electric automobiles and the like. However, the current commercial lithium ion batteries have poor adaptability to ambient temperature, side reactions within the battery occur rapidly at too high temperatures (> 45 ℃) and kinetic transport is retarded at too low temperatures (< 0 ℃), and too high or too low temperatures can negatively affect the performance of the battery, even raise safety issues, which severely limit its application in a wider temperature range scenario. In the existing solution of high/low temperature performance of lithium ion battery, vinyl sulfate, propylene sulfate and the like have a certain improvement effect on the high temperature or low temperature performance of the battery, but cannot give consideration to both the high and low temperature performance. Therefore, development of a wide temperature electrolyte solution having both high and low temperature properties is desired. Disclosure of Invention The invention aims to provide a wide-temperature electrolyte and a lithium ion battery which have high and low temperature performances. In order to achieve the above purpose, the invention adopts the following technical scheme: The invention provides a wide-temperature electrolyte, which comprises a nonaqueous organic solvent, lithium salt and an additive, wherein the additive comprises an additive A, and the structural formula of the additive A is as follows: Wherein R 1、R2 is each independently selected from nitro, substituted or unsubstituted hydrocarbyl, cyano, halogen, or hydrogen, at least one of the R 1、R2 is not hydrogen, and when one of the R 1、R2 is hydrogen, the other is nitro. According to the invention, R 1、R2 is introduced into the para position of the six-membered ring of the propylene sulfate, so that SEI components with higher stability can be formed on the surface of the graphite negative electrode, and the high-temperature and low-temperature performances of the battery can be simultaneously improved. Herein, the hydrocarbon group includes saturated or unsaturated alkyl groups, alkenyl groups, alkynyl groups, and phenyl groups. Preferably, each R 1、R2 is independently selected from nitro, substituted or unsubstituted alkyl with 1-6 carbon atoms or hydrogen, and the substituent of the alkyl is halogen. In some embodiments, the hydrocarbon group is selected from an alkyl group having 1 to 6 carbon atoms or a phenyl group. Further, the alkyl is selected from methyl, ethyl, propyl, butyl, pentyl, hexyl. Still further, the propyl group includes n-propyl and isopropyl groups, the butyl group includes n-butyl, sec-butyl, tert-butyl and isobutyl groups, the pentyl group includes n-pentyl and isopentyl groups, and the hexyl group includes cyclohexyl groups. Preferably, the halogen is fluorine. In some embodiments, R 1 is nitro, and R 2 is selected from nitro, hydrogen, alkyl with 1-6 carbon atoms or phenyl. In some embodiments, R 1、R2 is independently selected from alkyl groups having 1 to 3 carbon atoms or halogen. In some embodiments, the additive a is selected from one or more of the substances represented by the following structural formulas: Further, at least one of the R 1、R2 groups is a nitro group, and when only one is a nitro group, the other is selected from alkyl groups having 1 to 3 carbon atoms. Preferably, the additive a accounts for 0.1-5% of the total mass of the electrolyte, and more preferably 0.5-2.5%, for example 0.5%, 0.8%, 1%, 1.3%, 1.5%, 1.8%, 2%, 2.5%. Preferably, the compound of formula IAnd (3) reacting the substances with thionyl chloride in the presence of chloroform, regulating the pH value of a system to be neutral or alkaline after the reaction is finished, extracting and washing to obtain an intermediate, and reacting the intermediate with periodic acid in the presence of a catalyst to obtain the additive A, wherein R 1、R2 in the structural formula I is the same as R 1、R2 in the additive A. Preferably, the reaction temperature of the substance shown in the structural formula I and thionyl chloride is controlled to be 60-80 ℃, and more preferably 65-75 ℃. Preferably, the reaction temperature of the intermediate and the periodic acid is controlled to be-10 ℃, and more preferably-5 ℃. Preferably, the catalyst is ruthenium trichloride trihydrate. Further preferably, the molar ratio of the substance represented by the struct