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CN-122025833-A - Lithium-sulfur battery, electrolyte and electric equipment

CN122025833ACN 122025833 ACN122025833 ACN 122025833ACN-122025833-A

Abstract

The application discloses a lithium sulfur battery, electrolyte and electric equipment, which belong to the field of secondary batteries, wherein the lithium sulfur battery comprises an anode plate, electrolyte and a cathode plate, the electrolyte comprises a first electrolyte and a second electrolyte, the first electrolyte comprises thioether, and the second electrolyte comprises electrolyte salt and a solvent, wherein the mass concentration of the electrolyte salt in the electrolyte salt and the solvent is greater than or equal to 5mol/L. The lithium sulfur battery has excellent specific capacity and cycle performance.

Inventors

  • LIANG ZIBIN
  • XU YIDA
  • ZHANG XINXIN
  • GUO BINGKUN

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20241111

Claims (20)

  1. 1. A lithium sulfur battery is characterized by comprising a positive electrode plate, an electrolyte and a negative electrode plate, The electrolyte comprises a first electrolyte and a second electrolyte, the first electrolyte comprises thioether, the second electrolyte comprises electrolyte salt and a solvent, and the mass concentration of the electrolyte salt in the electrolyte salt and the solvent is greater than or equal to 5mol/L.
  2. 2. The lithium sulfur battery of claim 1 wherein the thioether comprises R1-S n -R2, wherein n = 2-3, and R1 and R2 each independently comprise one or more of methyl, phenyl, ethyl, n-propyl, isopropyl, or propenyl.
  3. 3. The lithium sulfur battery of claim 2 wherein R1 and R2 each independently comprise one or more of methyl or phenyl.
  4. 4. The lithium sulfur battery of any of claims 1-3 wherein the thioether comprises one or more of CH 3 -S-S-CH 3 、C 6 H 5 -S-S-S-C 6 H 5 、C 6 H 5 -S-S-C 6 H 5 、C 6 H 5 -S-S-S-CH 3 、C 6 H 5 -S-S-CH 3 、CH 3 CH 2 -S-S-CH 2 CH 3 、CH 3 CH 2 -S-S-S-CH 2 CH 3 、CH 3 CH 2 CH 2 -S-S-CH 2 CH 2 CH3、CH 3 CH 2 CH 2 -S-S-S-CH 2 CH 2 CH 3 、CH 3 -S-S-CH 2 CH 3 、CH 3 -S-S-S-CH 2 CH 3 、CH 3 -S-S-CH 2 CH 2 CH 3 、CH 3 -S-S-S-CH 2 CH 2 CH 3 or CH 3 -S-S-S-CH 3 .
  5. 5. The lithium sulfur battery of any of claims 1-4 wherein the first electrolyte further comprises a first solvent comprising one or more of 1, 2-dimethoxypropane, dimethoxymethane, ethylene glycol dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, pentaethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, 1, 3-dioxane, or dimethyl ether.
  6. 6. The lithium sulfur battery of any of claims 1-5 wherein the sulfide species is present in the first electrolyte in an amount ranging from 1mol/L to 10mol/L.
  7. 7. The lithium sulfur battery according to any one of claims 1 to 6, wherein an amount concentration of a substance of the electrolyte salt in the second electrolyte is 5mol/L or more.
  8. 8. The lithium sulfur battery according to any one of claims 1 to 7, wherein an amount concentration of a substance of the electrolyte salt in the second electrolyte is 5mol/L to 10mol/L.
  9. 9. The lithium sulfur battery of any of claims 1-8 wherein the electrolyte salt comprises one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis-fluorosulfonimide, lithium bis-trifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalato borate, lithium difluorooxalato phosphate, or lithium tetrafluorooxalato phosphate.
  10. 10. The lithium sulfur battery of any of claims 1-9 wherein the solvent comprises one or more of 1, 2-dimethoxypropane, dimethoxymethane, ethylene glycol dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, pentaethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, 1, 3-dioxolane, or dimethyl ether.
  11. 11. The lithium sulfur battery of any of claims 1-10 wherein the second electrolyte further comprises a diluent, the diluent comprises 1H, 5H-octafluoropentyl-1, 2-tetrafluoroethyl ether one or more of bis (2, 2-trifluoroethyl) ether or 1, 2-tetrafluoroethyl 2, 3-tetrafluoropropyl ether.
  12. 12. The lithium sulfur battery of any of claims 1-11 wherein the ratio of the volumes of the first electrolyte and the second electrolyte in the electrolyte is (5:95) - (30:70).
  13. 13. The lithium sulfur battery of any of claims 1-12 wherein the positive electrode sheet comprises a positive electrode active material comprising conductive carbon and sulfur.
  14. 14. The lithium sulfur battery of claim 13 wherein the mass ratio of the conductive carbon to the sulfur is (1:9) - (5:5).
  15. 15. The lithium sulfur battery of any of claims 1-14 wherein the positive electrode sheet comprises a current collector and a positive electrode slurry disposed on at least one side of the current collector, the positive electrode slurry comprising a positive electrode active material and the electrolyte.
  16. 16. The lithium-sulfur battery according to claim 15, wherein the mass ratio of the components in the positive electrode slurry is positive electrode active material electrolyte conductive agent= (10-50): (50-90): (0.5-10).
  17. 17. An electrolyte, characterized in that the electrolyte comprises a first electrolyte and a second electrolyte, the first electrolyte comprises thioether, the second electrolyte comprises electrolyte salt and a solvent, and the mass concentration of the electrolyte salt in the electrolyte salt and the solvent is greater than or equal to 5mol/L.
  18. 18. The electrolyte of claim 17 wherein the thioether comprises R1-S n -R2, wherein n = 2-3, and wherein R1 and R2 each independently comprise one or more of methyl, phenyl, ethyl, n-propyl, isopropyl, or propenyl.
  19. 19. The electrolyte of claim 18 wherein R1 and R2 each independently comprise one or more of methyl or phenyl.
  20. 20. The electrolyte of any one of claims 17-19 wherein the thioether comprises one or more of CH 3 -S-S-CH 3 、C 6 H 5 -S-S-S-C 6 H 5 、C 6 H 5 -S-S-C 6 H 5 、C 6 H 5 -S-S-S-CH 3 、C 6 H 5 -S-S-CH 3 、CH 3 CH 2 -S-S-CH 2 CH 3 、CH 3 CH 2 -S-S-S-CH 2 CH 3 、CH 3 CH 2 CH 2 -S-S-CH 2 CH 2 CH3、CH 3 CH 2 CH 2 -S-S-S-CH 2 CH 2 CH 3 、CH 3 -S-S-CH 2 CH 3 、CH 3 -S-S-S-CH 2 CH 3 、CH 3 -S-S-CH 2 CH 2 CH 3 、CH 3 -S-S-S-CH 2 CH 2 CH 3 or CH 3 -S-S-S-CH 3 .

Description

Lithium-sulfur battery, electrolyte and electric equipment Technical Field The application belongs to the field of secondary batteries, and particularly relates to a lithium-sulfur battery, an electrolyte and electric equipment. Background The secondary battery is widely applied to energy storage power supply systems such as hydraulic power, firepower, wind power, solar power stations and the like, and a plurality of fields such as electric tools, electric bicycles, electric motorcycles, electric automobiles, military equipment, aerospace and the like. The lithium-sulfur battery is a lithium battery with sulfur element as a battery anode and metal lithium as a cathode. The elementary sulfur has the characteristics of abundant reserves in the earth, low price, environmental friendliness and the like. The lithium sulfur battery using sulfur as the positive electrode material has higher material theoretical specific capacity and battery theoretical specific energy which respectively reach 1675mAh/g and 2600Wh/kg, however, the intermediate product lithium polysulfide of the lithium sulfur battery is easy to dissolve in electrolyte and can shuttle to the negative electrode metal lithium side, and side reaction occurs with the metal lithium to consume the metal lithium and form non-conductive lithium sulfide to cover the surface of the metal lithium, so that the capacity and the cycle performance are reduced. Disclosure of Invention In view of the technical problems in the background art, the application provides a lithium-sulfur battery, which aims to improve the capacity and the cycle performance of the lithium-sulfur battery. In order to achieve the above object, a first aspect of the present application provides a lithium-sulfur battery comprising a positive electrode tab, an electrolyte and a negative electrode tab, the electrolyte comprising a first electrolyte comprising a thioether and a second electrolyte comprising an electrolyte salt and a solvent, wherein the electrolyte salt has an amount concentration of a substance of 5mol/L or more in the electrolyte salt and the solvent. The lithium sulfur battery at least comprises the following beneficial effects that the lithium sulfur battery comprises two electrolytes, so that shuttling of intermediate product lithium polysulfide can be restrained, contact of a positive electrode can be improved, and capacity and cycle performance of the lithium sulfur battery can be improved. In some embodiments, the thioether comprises R1-S n -R2, wherein n = 2-3, and R1 and R2 each independently comprise one or more of methyl, phenyl, ethyl, n-propyl, isopropyl, or propenyl. Thus, the capacity and cycle performance of the lithium-sulfur battery can be improved. In some embodiments, R1 and R2 each independently comprise one or more of methyl or phenyl. Thus, the capacity and cycle performance of the lithium-sulfur battery can be improved. In some embodiments, the thioether comprises one or more of CH3-S-S-CH3、C6H5-S-S-S-C6H5、C6H5-S-S-C6H5、C6H5-S-S-S-CH3、C6H5-S-S-CH3、CH3CH2-S-S-CH2CH3、CH3CH2-S-S-S-CH2CH3、CH3CH2CH2-S-S-CH2CH2CH3、CH3CH2CH2-S-S-S-CH2CH2CH3、CH3-S-S-CH2CH3、CH3-S-S-S-CH2CH3、CH3-S-S-CH2CH2CH3、CH3-S-S-S-CH2CH2CH3 or CH 3-S-S-S-CH3. Thus, the capacity and cycle performance of the lithium-sulfur battery can be improved. In some embodiments, the first electrolyte further comprises a first solvent comprising one or more of 1, 2-dimethoxypropane, dimethoxymethane, ethylene glycol dimethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, pentaethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, 1, 3-dioxolane, or dimethyl ether. Thus, the capacity and cycle performance of the lithium-sulfur battery can be improved. In some embodiments, the sulfide is present in the first electrolyte in an amount ranging from 1mol/L to 10mol/L. Thus, the capacity and cycle performance of the lithium-sulfur battery can be improved. In some embodiments, the second electrolyte solution has an electrolyte salt material concentration of greater than or equal to 5mol/L. Thus, the capacity and cycle performance of the lithium-sulfur battery can be improved. In some embodiments, the second electrolyte solution has an amount concentration of the substance of the electrolyte salt of 5mol/L to 10mol/L. Thus, the capacity and cycle performance of the lithium-sulfur battery can be improved. In some embodiments, the electrolyte salt comprises one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethanesulfonyl imide, lithium trifluoro