Search

CN-122025812-A - Electrolyte additive composition, electrolyte and lithium ion battery

CN122025812ACN 122025812 ACN122025812 ACN 122025812ACN-122025812-A

Abstract

The application discloses an electrolyte additive composition, electrolyte and a lithium ion battery, wherein the electrolyte additive composition consists of an additive A and an additive B, the molecular structure of the additive A is shown as a formula (I), and the molecular structure of the additive B is shown as a formula (II): Wherein R 1 、R 2 、R 3 is independently selected from one of hydrogen atom, halogen atom, amino, C1-C4 alkyl, methoxy, methanesulfonyl, ethanesulfonyl, fluorosulfonyl, trifluoromethyl, phenyl, isocyano and COORa in the formula (II), ra in COORa is C1-C3 alkyl, and n is any integer between 0 and 3. According to the application, through the mutual matching of two specific additives, the high-voltage cycle life, the high-temperature storage performance and the impedance increase in the cycle process of the lithium ion battery are obviously improved.

Inventors

  • SHU XIN
  • Wu Zhangsu
  • YUAN QUAN
  • LI BAOZHANG
  • GAO DIAN

Assignees

  • 合肥华彩新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260212

Claims (10)

  1. 1. An electrolyte additive composition is characterized by comprising an additive A and an additive B, wherein the molecular structure of the additive A is shown as a formula (I), and the molecular structure of the additive B is shown as a formula (II): ; in the formula (II), R 1 、R 2 、R 3 is independently selected from one of hydrogen, halogen, amino, C1-C4 alkyl, methoxy, methanesulfonyl, ethanesulfonyl, fluorosulfonyl, trifluoromethyl, phenyl, isocyano or-COORa, wherein Ra is C1-C3 alkyl, and n is any integer between 0 and 3.
  2. 2. The electrolyte additive composition according to claim 1, wherein the additive B is selected from any one or a mixture of two or more of the compounds SiN01 to SiN 06: 。
  3. 3. The electrolyte additive composition of claim 1, wherein the mass ratio of additive a to additive B is from 1:5 to 5:1.
  4. 4. An electrolyte comprising an electrolyte lithium salt, an organic solvent and the electrolyte additive composition of any one of claims 1-3.
  5. 5. The electrolyte of claim 4 wherein said additive A is present in an amount of 0.01wt% to 5wt% and said additive B is present in an amount of 0.01wt% to 5wt% based on the total mass of said electrolyte.
  6. 6. The electrolyte of claim 4 wherein the electrolyte lithium salt is at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethanesulfonyl imide, lithium bis-oxalato borate, lithium difluoro-phosphate, and lithium perchlorate.
  7. 7. The electrolyte of claim 4, wherein the electrolyte lithium salt is present in the electrolyte in an amount of 5 20wt%。
  8. 8. The electrolyte according to claim 4, wherein the organic solvent is ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylene propylene carbonate, methylpropyl carbonate, 1,4 At least one of butyrolactone, methyl propionate, methyl butyrate, ethyl acetate, ethyl propionate, propyl propionate, or ethyl butyrate.
  9. 9. A lithium ion battery comprising a positive electrode, a negative electrode, a separator, and the electrolyte of any one of claims 4-8.
  10. 10. The lithium ion battery of claim 9, wherein the positive electrode comprises a positive electrode active material, the positive electrode active material is lithium nickel cobalt manganate having a chemical formula of LiNixCoyMnzO 2 , 0< x <1,0< y <1,0< z <1, x+y+z = 1; Preferably, the positive electrode active material is at least one of LiNi 1/3 Co 1/3 Mn 1/3 O 2 、LiNi 0.5 Co 0.2 Mn 0.3 O 2 、LiNi 0.6 Co 0.2 Mn 0.2 O 2 and LiNi 0.8 Co 0.1 Mn 0.1 O 2 .

Description

Electrolyte additive composition, electrolyte and lithium ion battery Technical Field The application belongs to the technical field of lithium ion battery electrolyte, and particularly relates to an electrolyte additive composition, an electrolyte containing the electrolyte additive composition and a lithium ion battery assembled based on the electrolyte. Background With the improvement of energy density requirements of electric automobiles and energy storage systems, positive electrode materials with high working voltage (more than or equal to 4.45vvs.Li/Li +) have become key to the development of lithium ion batteries. However, under high pressure conditions, the carbonate solvents in the electrolyte are subject to irreversible oxidative decomposition, yielding highly reactive alkyl oxygen radicals (e.g., RO. Cndot.). These free radicals can initiate chain side reactions, which not only consume electrolyte continuously, generate gas, but also attack the cathode material, resulting in dissolution of transition metal ions, destruction of the crystal structure, and formation of an unstable organic-rich cathode-electrolyte interface (CEI film), ultimately leading to rapid decay of battery capacity and reduced cycle life. To address the above problems, the prior art has mainly dealt with both material modification and electrolyte additives. Among them, electrolyte engineering is widely studied because of its good process compatibility, but conventional additives (such as vinylene carbonate, fluoroethylene carbonate, etc.) or their improvements have significant limitations. For example, some of the prior art (such as CN107910586A, CN107394268a, etc.) mainly complexes acidic materials (such as HF) in electrolytes through specific functional groups (such as piperidinyl, amino groups), or improves film formation and high temperature performance through siloxane bonds, sulfonyl groups, etc., and the mechanism of action focuses on proton capture or physical barriers, and generally lacks efficient and targeted electron transfer capability for scavenging highly active alkyl oxygen radicals. Other schemes (such as CN114069049 a) have multifunctional designs, but still cannot quench the free radical generated at high pressure of 4.45V and above effectively, and fail to solve the core problems of the free radical attack on the positive lattice oxygen and initiation of the chain reaction. In general, the existing electrolyte additive strategies, especially for high-voltage systems, generally have the problems that alkyl oxygen free radicals generated under high voltage cannot be efficiently and targeted captured and quenched, so that a positive electrode-electrolyte interface (CEI) is unstable, side reactions continuously occur, and the high-voltage cycle performance of a battery is deteriorated. Disclosure of Invention In view of the above, a primary object of the present application is to provide an electrolyte additive composition, which is composed of an additive a and an additive B, wherein the additive a is a lithium salt additive containing nitroxide free radicals and-NH-SO 3- anionic groups, the additive B is a silicon-based isocyanic acid compound, and the two additives are matched with each other, SO that the high-voltage cycle life, the high-temperature storage performance and the impedance increase in the cycle process of the lithium ion battery are significantly improved. In order to achieve the above purpose, the present application adopts the following technical scheme: One aspect of the application discloses an electrolyte additive composition, which consists of an additive A and an additive B, wherein the molecular structure of the additive A is shown as a formula (I), and the molecular structure of the additive B is shown as a formula (II): ; In the formula (II), R1, R2 and R3 are respectively and independently selected from one of hydrogen, halogen, amino, C1-C4 alkyl, methoxy, methanesulfonyl, ethanesulfonyl, fluorosulfonyl, trifluoromethyl, phenyl, isocyano or-COORa, wherein Ra is C1-C3 alkyl, and n is any integer between 0 and 3. In another aspect of the application, an electrolyte is disclosed that includes an electrolyte lithium salt, an organic solvent, and an electrolyte additive composition as described herein. Another aspect of the application discloses a lithium ion battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte as described herein. The application has the beneficial effects that: The electrolyte additive composition consists of an additive A and an additive B, wherein the additive A is a lithium salt additive containing nitrogen-oxygen free radicals and-NH-SO 3- anionic groups, and the additive B is a silicon-based isocyanic acid compound which are matched with each other, SO that the high-voltage cycle life, the high-temperature storage performance and the impedance growth in the cycle process of the lithium ion battery are obviously improved,