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CN-122025731-A - Solid-state battery, preparation method thereof, battery device, energy storage system and electric equipment

CN122025731ACN 122025731 ACN122025731 ACN 122025731ACN-122025731-A

Abstract

The embodiment of the application relates to the field of energy storage, and provides a solid-state battery, a preparation method thereof, a battery device, an energy storage system and electric equipment. The solid-state battery comprises a positive plate, a solid electrolyte membrane and a negative plate, wherein the solid electrolyte membrane comprises a carboxyl modified fluorinated cellulose nanofiber base membrane, and lithium salt and ionic liquid which are dispersed in the carboxyl modified fluorinated cellulose nanofiber base membrane, and the carboxyl modified fluorinated cellulose nanofiber base membrane has a cross-linked structure. The solid electrolyte membrane has higher ionic conductivity, excellent interface adaptability and long-term structural stability in a high-temperature environment, and the application of the solid electrolyte membrane in a solid battery is beneficial to improving the high-temperature cycle stability of the solid battery.

Inventors

  • CHEN JING
  • SHI HAOTIAN
  • YANG ZIXIANG
  • WU YUHAO
  • ZHANG LUHUA

Assignees

  • 浙江晶科储能有限公司

Dates

Publication Date
20260512
Application Date
20260410

Claims (17)

  1. 1. The solid-state battery comprises a positive plate, a solid electrolyte membrane and a negative plate, and is characterized in that the solid electrolyte membrane comprises a carboxyl-modified fluorinated cellulose nanofiber base membrane, and lithium salt and ionic liquid dispersed in the carboxyl-modified fluorinated cellulose nanofiber base membrane, wherein the carboxyl-modified fluorinated cellulose nanofiber base membrane has a cross-linked structure.
  2. 2. The solid-state battery according to claim 1, wherein the carboxyl group-modified fluorinated cellulose nanofiber base film has a crosslinking degree of 20 to 80%, and/or the carboxyl group-modified fluorinated cellulose nanofiber base film has a water contact angle of 85 to 120 °, and/or the carboxyl group-modified fluorinated cellulose nanofiber base film has a porosity of 35 to 75%, and/or the carboxyl group-modified fluorinated cellulose nanofiber base film has an average pore diameter of 10 to 300nm.
  3. 3. The solid-state battery according to claim 1, wherein the mass content of carboxyl groups in the carboxyl group-modified fluorinated cellulose nanofiber base film is 5-8%, and/or the mass content of fluorine elements in the carboxyl group-modified fluorinated cellulose nanofiber base film is 1-28%, and/or the diameter of cellulose nanofibers in the carboxyl group-modified fluorinated cellulose nanofiber base film is 3-20 nm, and the length is 0.3-5 μm.
  4. 4. The solid-state battery according to any one of claims 1 to 3, wherein the ionic liquid comprises a cation selected from any one or more of N-methyl-N-propylpyrrolidine ion, 1-ethyl-3-methylimidazole ion, 1-butyl-3-methylimidazole ion, N-methyl-N-butylpyrrolidine ion and N-methyl-N-ethylpyrrolidine ion and an anion selected from any one or more of bis-fluorosulfonimide ion, bis-trifluoromethylsulfonimide ion and fluoro-trifluoromethylsulfonimide ion; And/or the lithium salt is selected from any one or more of lithium bis (fluorosulfonyl) imide, lithium bis (trifluoromethylsulfonyl) imide, lithium hexafluorophosphate and lithium perchlorate.
  5. 5. The solid-state battery according to claim 4, wherein the ionic liquid is a combination of N-methyl-N-propyl pyrrolidine difluoro-sulfonyl imide and 1-ethyl-3-methylimidazole difluoro-sulfonyl imide, and the mass ratio of the N-methyl-N-propyl pyrrolidine difluoro-sulfonyl imide to the 1-ethyl-3-methylimidazole difluoro-sulfonyl imide is (1:9) to (9:1).
  6. 6. A solid state battery according to any one of claims 1 to 3, wherein the crosslinked structure is a three-dimensional crosslinked structure formed by urethane bond connection.
  7. 7. A solid-state battery according to any one of claims 1 to 3, wherein the ratio of the total mass of the lithium salt and the ionic liquid to the mass of the lithium salt is 100 (5-35), and/or the ratio of the total mass of the lithium salt and the ionic liquid to the mass of the carboxyl-modified fluorinated cellulose nanofiber base membrane is (60-90): 5-30.
  8. 8. A solid state battery according to claim 1 to 3, wherein the solid state electrolyte membrane has a thickness of 20 to 150 μm, and/or the solid state electrolyte membrane has an ionic conductivity of not less than 3X 10 -3 S/cm at 85 ℃, and/or the solid state electrolyte membrane has a lithium ion migration number of not less than 0.4 at 85 ℃, and/or the solid state electrolyte membrane has a storage modulus of 5 to 25MPa at 85 ℃, a tensile strength of 10 to 30MPa, an elongation at break of 20 to 200%, and/or the solid state electrolyte membrane has a linear dimensional change rate of <2% at 300 cycles of-20 to 85 ℃, and/or the solid state electrolyte membrane has an oxidation stability potential of not less than 4.4V at 85 ℃, and/or the solid state electrolyte membrane has a decomposition temperature of not less than 195 ℃, and/or the solid state electrolyte membrane has an interfacial resistance of not more than 130 Ω cm 2 .
  9. 9. A preparation method of a solid-state battery, stack positive pole piece, solid electrolyte membrane and negative pole piece sequentially, hot-press get the naked electric core, put the said naked electric core into battery case to encapsulate, get the said solid-state battery, characterized by that, the preparation step of the said solid electrolyte membrane includes: S1, mixing raw materials comprising cellulose, sodium hypochlorite, a co-oxidant, a catalyst, a pH regulator and water, and performing an oxidation reaction to obtain carboxyl modified cellulose; S2, carrying out defibration treatment on the carboxyl modified cellulose to obtain carboxyl modified cellulose nanofiber; S3, mixing raw materials comprising the carboxyl modified cellulose nanofiber, a fluorinating agent, a proton acceptor and a first solvent, and performing fluorination reaction to obtain the carboxyl modified fluorinated cellulose nanofiber; S4, mixing the carboxyl modified fluorinated cellulose nanofiber with a second solvent, coating the mixture on a substrate, and drying the mixture to obtain an uncrosslinked base film; S5, mixing the uncrosslinked base film, a crosslinking agent and a third solvent, and then performing crosslinking treatment to obtain a carboxyl modified fluorinated cellulose nanofiber base film with a crosslinked structure; S6, mixing the carboxyl modified fluorinated cellulose nanofiber base membrane with the cross-linked structure, lithium salt and ionic liquid to obtain the solid electrolyte membrane.
  10. 10. The method according to claim 9, wherein the mass ratio of the cellulose, the co-oxidizing agent and the catalyst is 100 (5-20): 0.5-5, and/or the molar ratio of the available chlorine content in the sodium hypochlorite to the cellulose is (2-10): 1, and/or the pH of the solution in the oxidation reaction is 10-11; and/or the temperature of the oxidation reaction is 15-30 ℃, and/or the time of the oxidation reaction is 1-6 hours; and/or the carboxyl amount in each gram of cellulose in the carboxyl modified cellulose is 1.2-1.5 mmol; and/or the diameter of the cellulose nanofiber in the carboxyl modified cellulose nanofiber is 3-20 nm, and the length of the cellulose nanofiber is 0.3-5 mu m.
  11. 11. The method according to claim 9, wherein the ratio of the fluorinating agent to the hydroxyl groups in the carboxyl-modified cellulose nanofibers is (0.1 to 2.0): 1 and/or the ratio of the proton acceptor to the fluorinating agent is (1 to 3): 1; and/or the temperature of the fluorination reaction is 20-80 ℃, and/or the time of the fluorination reaction is 2-24 hours; and/or the molar ratio of fluorine to hydroxyl in the carboxyl modified fluorinated cellulose nanofiber is (0.05-0.8): 1.
  12. 12. The method for producing a solid-state battery according to any one of claims 9 to 11, wherein the ratio by mass of the uncrosslinked base film to the crosslinking agent is 100 (3 to 12); And/or the temperature of the crosslinking treatment is 40-120 ℃, and/or the time of the crosslinking treatment is 2-24 hours.
  13. 13. The method for producing a solid-state battery according to any one of claims 9 to 11, wherein the co-oxidizing agent is selected from any one or more of sodium bromide, potassium bromide, sodium chloride, and calcium hypochlorite; and/or the number of the groups of groups, the catalyst is selected from any one or more of 2, 6-tetramethyl piperidine-1-oxygen free radical, 4-acetamido-2, 6-tetramethyl piperidine-1-oxygen free radical and 4-hydroxy-2, 6-tetramethyl piperidine-1-oxygen free radical; and/or the pH regulator is selected from any one or more of sodium hydroxide, potassium hydroxide, sodium carbonate and sodium bicarbonate; And/or the fluorinating agent is selected from 1-chloromethyl-4-fluoro-1, 4-diazabicyclo [2.2.2] octane tetrafluoroborate, diethylaminosulfur trifluoride, 1- (chloromethyl) -4-fluoro-1, 4-diazabicyclo [2.2.2] octane-1, 4-di Any one or more of a ditetrafluoroborate and an N-fluoro-bis-benzenesulfonimide, and/or the proton acceptor is selected from any one or more of triethylamine, pyridine and potassium carbonate, and/or the first solvent is selected from any one or more of N-methylpyrrolidone, N-dimethylformamide, dimethyl sulfoxide and acetonitrile; And/or the second solvent is selected from any one or more of N-methyl pyrrolidone, N-dimethylformamide, dimethyl sulfoxide and acetonitrile; And/or the cross-linking agent is selected from any one or more of 1, 6-hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, 1, 4-butylene diisocyanate, 1, 12-dodecane diisocyanate, 4' -dicyclohexylmethane diisocyanate and trimethylolpropane triisocyanate, and/or the third solvent is selected from any one or more of tetrahydrofuran, acetonitrile and toluene; And/or the lithium salt is selected from any one or more of lithium bis (fluorosulfonyl) imide, lithium bis (trifluoromethylsulfonyl) imide, lithium hexafluorophosphate and lithium perchlorate; And/or the ionic liquid is a combination of N-methyl-N-propyl pyrrolidine difluoro sulfonyl imide and 1-ethyl-3-methylimidazole difluoro sulfonyl imide, and the mass ratio of the N-methyl-N-propyl pyrrolidine difluoro sulfonyl imide to the 1-ethyl-3-methylimidazole difluoro sulfonyl imide is (1:9) - (9:1).
  14. 14. The method for producing a solid-state battery according to any one of claims 9 to 11, wherein the ratio of the total mass of the lithium salt and the ionic liquid to the mass of the lithium salt is 100 (5 to 35), and/or the ratio of the total mass of the lithium salt and the ionic liquid to the mass of the carboxyl-modified fluorinated cellulose nanofiber-based film having a crosslinked structure is (60 to 90): 5 to 30.
  15. 15. A battery device comprising a plurality of unit cells, characterized in that the unit cells are the solid-state battery according to any one of claims 1 to 8 or the solid-state battery produced by the production method of the solid-state battery according to any one of claims 9 to 14.
  16. 16. An energy storage system comprising a housing provided with a receiving cavity, wherein the battery device of claim 15 is disposed within the receiving cavity.
  17. 17. A powered device comprising the energy storage system of claim 16, the energy storage system to provide power to the powered device.

Description

Solid-state battery, preparation method thereof, battery device, energy storage system and electric equipment Technical Field The application relates to the field of energy storage, in particular to a solid-state battery, a preparation method thereof, a battery device, an energy storage system and electric equipment. Background With the rapid development of electric vehicles, energy storage systems and high-power electronic devices, there is an increasing demand for lithium ion batteries capable of stably operating in a high-temperature environment. Conventional liquid electrolytes have problems of solvent evaporation, thermal runaway risk, narrowing of electrochemical window, etc. at high temperature, while solid electrolytes are considered ideal choices for high temperature batteries due to their intrinsic thermal stability and safety advantages. However, existing solid state electrolyte technology still faces many challenges in high temperature applications. Disclosure of Invention The embodiment of the application provides a solid-state battery, a preparation method thereof, a battery device, an energy storage system and electric equipment, and aims to solve the problems of poor high-temperature cycling stability of the solid-state battery caused by rapid decrease of ion conductivity, increase of interface impedance, insufficient mechanical strength and poor thermal stability of a solid-state electrolyte in a high-temperature environment in the prior art. In order to achieve the above object, according to one aspect of the present invention, there is provided a solid-state battery comprising a positive electrode sheet, a solid-state electrolyte membrane, and a negative electrode sheet, the solid-state electrolyte membrane comprising a carboxyl-modified fluorinated cellulose nanofiber base membrane and a lithium salt and an ionic liquid dispersed in the carboxyl-modified fluorinated cellulose nanofiber base membrane, wherein the carboxyl-modified fluorinated cellulose nanofiber base membrane has a crosslinked structure. Further, the crosslinking degree of the carboxyl modified fluorinated cellulose nanofiber base membrane is 20-80%, and/or the water contact angle of the carboxyl modified fluorinated cellulose nanofiber base membrane is 85-120 degrees, and/or the porosity of the carboxyl modified fluorinated cellulose nanofiber base membrane is 35-75%, and/or the average pore diameter of the carboxyl modified fluorinated cellulose nanofiber base membrane is 10-300 nm. Further, the mass content of carboxyl in the carboxyl modified fluorinated cellulose nanofiber base film is 5-8%, and/or the mass content of fluorine in the carboxyl modified fluorinated cellulose nanofiber base film is 1-28%, and/or the diameter of cellulose nanofiber in the carboxyl modified fluorinated cellulose nanofiber base film is 3-20 nm, and the length is 0.3-5 mu m. Further, the ionic liquid comprises cations and anions, wherein the cations are selected from any one or more of N-methyl-N-propyl pyrrolidine ion, 1-ethyl-3-methylimidazole ion, 1-butyl-3-methylimidazole ion, N-methyl-N-butyl pyrrolidine ion and N-methyl-N-ethylpyrrolidine ion, the anions are selected from any one or more of difluoro-sulfonyl imide ion, bis-trifluoro-methyl-sulfonyl imide ion and fluoro-trifluoro-methyl-sulfonyl imide ion, and/or the lithium salt is selected from any one or more of bis-fluoro-sulfonyl imide lithium, bis-trifluoro-methyl-sulfonyl imide lithium, hexafluorophosphate lithium and lithium perchlorate. Further, the ionic liquid is a combination of N-methyl-N-propyl pyrrolidine difluoro sulfonyl imide and 1-ethyl-3-methylimidazole difluoro sulfonyl imide, and the mass ratio of the N-methyl-N-propyl pyrrolidine difluoro sulfonyl imide to the 1-ethyl-3-methylimidazole difluoro sulfonyl imide is (1:9) - (9:1). Further, the crosslinked structure is a three-dimensional crosslinked structure formed by urethane linkage. Further, the ratio of the total mass of the lithium salt and the ionic liquid to the mass of the lithium salt is 100 (5-35), and/or the ratio of the total mass of the lithium salt and the ionic liquid to the mass of the carboxyl modified fluorinated cellulose nanofiber base membrane is (60-90): 5-30. Further, the solid electrolyte membrane has a thickness of 20-150 [ mu ] m, and/or the solid electrolyte membrane has an ionic conductivity of not less than 3X 10 -3 S/cm at 85 ℃, and/or the solid electrolyte membrane has a lithium ion migration number not less than 0.4 at 85 ℃, and/or the solid electrolyte membrane has a storage modulus of 5-25 MPa at 85 ℃, a tensile strength of 10-30 MPa, an elongation at break of 20-200%, and/or the solid electrolyte membrane has a linear dimension change rate of <2% when the solid electrolyte membrane is cycled for 300 cycles at-20-85 ℃, and/or the solid electrolyte membrane has an oxidation stability potential not less than 4.4V at 85 ℃, and/or the solid electrolyte membrane has a decomposition tempe