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CN-122025814-A - Lithium ion battery and application thereof

CN122025814ACN 122025814 ACN122025814 ACN 122025814ACN-122025814-A

Abstract

The invention provides a lithium ion battery and application thereof, wherein the lithium ion battery comprises a positive electrode plate, a negative electrode plate, a diaphragm, electrolyte and a first additive, wherein the negative electrode plate comprises a negative electrode material, the negative electrode material comprises a negative electrode active substance and a sulfur simple substance coated on the surface of the negative electrode active substance, the negative electrode active substance comprises a silicon material, the diaphragm is arranged between the positive electrode plate and the negative electrode plate, the electrolyte comprises an additive, and the structural formula of the first additive is shown as the formula (I); Wherein R1, R2, R3 and R4 are selected from at least one of H, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl or substituted or unsubstituted C1-C12 alkoxy, and when substituted, the substituent is halogen or C1-C12 alkyl. According to the lithium ion battery and the application thereof, provided by the invention, the expansion stress generated in the charging and discharging process of the silicon material can be restrained, and the cycle performance of the lithium ion battery is improved.

Inventors

  • YU LE
  • Hu Ajuan

Assignees

  • 远景动力技术(湖北)有限公司

Dates

Publication Date
20260512
Application Date
20260304

Claims (10)

  1. 1. A lithium ion battery, comprising: A positive electrode sheet; The negative electrode plate comprises a negative electrode material, wherein the negative electrode material comprises a negative electrode active substance and elemental sulfur coated on the surface of the negative electrode active substance, and the negative electrode active substance comprises a silicon material; a separator arranged between the positive electrode plate and the negative electrode plate, and An electrolyte comprising an additive, the additive comprising a first additive having the structural formula (I); Wherein R1, R2, R3 and R4 are selected from at least one of H, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl or substituted or unsubstituted C1-C12 alkoxy, and when substituted, the substituent is halogen or C1-C12 alkyl.
  2. 2. The lithium ion battery of claim 1, wherein the first additive is present in the electrolyte in an amount of 0.1wt% to 3wt%.
  3. 3. The lithium ion battery according to claim 1, wherein the content of the elemental sulfur in the negative electrode material is 0.1wt% to 2wt%.
  4. 4. The lithium ion battery of claim 1, wherein in the lithium ion battery, the mass ratio of the first additive to the elemental sulfur is 1:10 to 5:1.
  5. 5. The lithium ion battery according to claim 1, wherein the content of the first additive in the electrolyte is 0.5wt% to 1wt%, and/or the content of the elemental sulfur in the negative electrode material is 0.5wt% to 1wt%.
  6. 6. The lithium ion battery according to claim 1, wherein the electrolyte further comprises a lithium salt selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluorosulfonimide, lithium bis (trifluoromethyl) sulfonimide, lithium dioxaborate, lithium difluorodioxalate phosphate, lithium difluorophosphate or lithium trifluoromethane sulfonate, and the content of the lithium salt in the electrolyte is 10wt% to 15wt%.
  7. 7. The lithium ion battery of claim 1, wherein the electrolyte further comprises a non-aqueous solvent selected from one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, and fluoroethylene carbonate.
  8. 8. The lithium ion battery of claim 1, wherein the additive comprises a second additive comprising lithium difluorooxalato borate, the second additive being present in the electrolyte in an amount of 0.1wt% to 1wt%.
  9. 9. The lithium ion battery of claim 1, wherein the silicon material is selected from at least one of elemental silicon, a silicon oxygen material, or a silicon carbon composite.
  10. 10. An electronic device comprising a lithium-ion battery according to any one of claims 1-9.

Description

Lithium ion battery and application thereof Technical Field The invention relates to the technical field of power batteries, in particular to a lithium ion battery and application thereof. Background The lithium ion battery has the advantages of high voltage, high capacity, long cycle life, low self-discharge efficiency, good safety performance and the like, and is widely applied to the fields of 3C/digital products, electric automobiles, energy storage and the like. The negative electrode plate is an important component of the lithium ion battery and has a decisive influence on the electrochemical performance of the lithium ion battery. Among many factors, the negative electrode active material is an important component of the lithium ion battery, and has a particularly significant influence on the performance of the lithium ion battery. The silicon material has high specific capacity and high storage capacity, and the development of the silicon material gradually leads to the innovation of the energy storage field, but the silicon negative electrode has poor conductivity and high volume expansion rate during charge and discharge, so that the problems of electrode pulverization, short cycle life, serious gas production and the like are easily caused, and the development of the silicon negative electrode is limited. Disclosure of Invention The invention provides a lithium ion battery and application thereof, wherein the composition of electrolyte and the structure of a negative electrode material are regulated to form an SEI film with a three-dimensional net structure, so that the protection area is effectively increased, the expansion stress generated in the charging and discharging processes of a silicon material is uniformly dispersed, and particle fragmentation caused by stress concentration is reduced. In order to solve the above technical problems, the present invention provides a lithium ion battery, comprising: A positive electrode sheet; The negative electrode plate comprises a negative electrode material, wherein the negative electrode material comprises a negative electrode active substance and elemental sulfur coated on the surface of the negative electrode active substance, and the negative electrode active substance comprises a silicon material; a separator arranged between the positive electrode plate and the negative electrode plate, and An electrolyte comprising an additive, the additive comprising a first additive having the structural formula (I); Wherein R1, R2, R3 and R4 are selected from at least one of H, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl or substituted or unsubstituted C1-C12 alkoxy, and when substituted, the substituent is halogen or C1-C12 alkyl. In one embodiment of the present invention, the first additive is contained in the electrolyte in an amount of 0.1wt% to 3wt%. In an embodiment of the present invention, in the anode material, the content of the elemental sulfur is 0.1wt% to 2wt%. In an embodiment of the present invention, in the lithium ion battery, a mass ratio of the first additive to the elemental sulfur is 1:10 to 5:1. In one embodiment of the present invention, the first additive is contained in the electrolyte in an amount of 0.5wt% to 1wt%, and/or the elemental sulfur is contained in the anode material in an amount of 0.5wt% to 1wt%. In one embodiment of the present invention, the electrolyte further includes a lithium salt selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluorosulfonimide, lithium bis (trifluoromethyl) sulfonimide, lithium dioxalate borate, lithium difluorodioxalate phosphate, lithium difluorophosphate or lithium trifluoromethane sulfonate, and the content of the lithium salt in the electrolyte is 10wt% to 15wt%. In an embodiment of the present invention, the electrolyte further includes a non-aqueous solvent, and the non-aqueous solvent is selected from one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, and fluoroethylene carbonate. In an embodiment of the present invention, the additive includes a second additive including lithium difluorooxalato borate, and the second additive is contained in the electrolyte in an amount of 0.1wt% to 1wt%. In an embodiment of the present invention, the silicon material is at least one selected from elemental silicon, a silicon oxygen material, or a silicon carbon composite. The invention also provides electronic equipment comprising the lithium ion battery. In summary, the invention provides a lithium ion battery and application thereof, wherein the composition of electrolyte and the structure of a negative electrode material are regulated, the surface of a negative electrode active substance is coated with elemental sulfur, a first additive is added into the electrolyte, and when the lithium ion battery is charged for the first time to form an SE