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CN-122025775-A - In-situ solidified electrolyte, in-situ solid-state battery and preparation method of in-situ solid-state battery

CN122025775ACN 122025775 ACN122025775 ACN 122025775ACN-122025775-A

Abstract

The invention belongs to the technical field of batteries, and particularly relates to an in-situ solidified electrolyte, an in-situ solid-state battery and a preparation method thereof. The raw materials of the in-situ curing electrolyte comprise a polymerization monomer, an initiator, a redox shuttle agent and electrolyte, and the electrolyte is prepared by in-situ polymerization of the raw materials in a battery through constant current charging and heating. The oxidation-reduction shuttle agent is triggered to react under the self-balancing voltage by constant current charging, electric energy is converted into heat energy, and uniform heating of the inside of the battery is realized, so that the polymerization monomer is initiated to polymerize uniformly, and the solid electrolyte with good ionic conductivity and interface stability is formed.

Inventors

  • TAN LIYI
  • ZHU XINGBAO
  • ZHANG WENQIANG
  • LI XIAOLONG

Assignees

  • 合肥国轩高科动力能源有限公司

Dates

Publication Date
20260512
Application Date
20260113

Claims (10)

  1. 1. The in-situ curing electrolyte is characterized in that raw materials of the in-situ curing electrolyte comprise a polymerization monomer, an initiator, a redox shuttle agent and an electrolyte; The in-situ solidified electrolyte is prepared by constant-current charging-heating polymerization of the raw materials in a battery.
  2. 2. The cured in place electrolyte of claim 1 wherein the polymeric monomer is selected from one or more of methyl methacrylate, methacrylic acid, acrylic acid, acrylonitrile, N-methylolacrylamide, pentaerythritol tetraacrylate, pentaerythritol triacrylate, ethylene carbonate, and vinylene carbonate.
  3. 3. The cured in place electrolyte of claim 1 wherein the initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptonitrile, hydrogen peroxide, t-butyl peroxide, dibenzoyl peroxide, ammonium persulfate, sodium persulfate, and potassium persulfate.
  4. 4. The cured in place electrolyte of claim 1 wherein the redox shuttle is selected from one or more of 2, 6-tetramethylpiperidine oxide, 2, 5-di-tert-butyl-1, 4-dimethoxybenzene, 3, 5-di-tert-butyl-1, 2-dimethoxybenzene, 4-tert-butyl-1, 2-dimethoxybenzene, and ferrocene.
  5. 5. The cured in place electrolyte of claim 1 wherein the electrolyte comprises a lithium salt, a solvent, and an additive.
  6. 6. The cured in place electrolyte of claim 5 wherein the electrolyte meets at least one of the following conditions (1) - (3): (1) The lithium salt is selected from one or more of lithium hexafluorophosphate, lithium difluorophosphate, lithium tetrafluorooxalate phosphate, lithium dioxaborate, lithium difluorooxalate borate, lithium tetrafluoroborate, lithium sulfate, lithium trifluoromethanesulfonate, lithium perfluorobutylsulfonate, lithium perfluorooctylsulfonate, lithium difluorosulfonimide, lithium bistrifluoromethanesulfonimide, lithium carbonate, lithium hexafluoroantimonate, lithium hexafluoroarsenate, lithium perchlorate and lithium tetrachloroaluminate; (2) The solvent comprises one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ethyl acetate, ethyl propionate, propyl acetate, ethyl butyrate, fluoroethylene carbonate, methyl trifluoroethyl carbonate, 1, 2-dimethoxyethane, dioxolane, tetrahydrofuran, ethylene oxide and propylene oxide; (3) The additive comprises one or more of ethylene carbonate, fluoroethylene carbonate, ethylene sulfite, methylene methane disulfonate, propenyl-1, 3-sultone, 1, 3-propane sultone, ethylene sulfate, tri (trimethylsilane) phosphate and ethylene glycol bis (propionitrile) ether.
  7. 7. An in-situ solid state battery, characterized in that the in-situ solid state battery comprises the in-situ cured electrolyte according to any one of claims 1-6.
  8. 8. The in-situ solid state battery of claim 7, wherein the in-situ solid state battery satisfies at least one of the following conditions (4) - (13): (4) The in-situ solidification battery also comprises a positive pole piece, a negative pole piece and a diaphragm; (5) The positive electrode plate comprises a current collector and a positive electrode material layer coated on the surface of the positive electrode current collector; (6) The positive electrode material layer comprises a positive electrode active material, a conductive agent and a binder; (7) The negative electrode plate comprises a current collector and a negative electrode material layer coated on the surface of the negative electrode current collector; (8) The negative electrode material layer comprises a negative electrode active material, a conductive agent and a binder; (9) The positive electrode active material is selected from one or more of lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium cobalt oxide, lithium manganese iron phosphate and lithium nickel cobalt aluminate; (10) The negative electrode active material is selected from one or more of graphite, metallic lithium alloy, silicon carbon material, tin-based material and silicon oxygen material; (11) The conductive agent is selected from one or more of conductive carbon black, conductive graphite, carbon fiber and carbon nano tube; (12) The adhesive is selected from one or more of styrene-butadiene rubber, nitrile rubber, polyvinylidene fluoride and polytetrafluoroethylene, or (13) The mass ratio of the positive electrode active material or the negative electrode active material, the conductive agent and the binder is 80-96:2-10:2-10.
  9. 9. A method of preparing an in-situ solid state battery as claimed in claim 7 or 8, characterized in that the method comprises the steps of: s1, assembling a positive pole piece, a negative pole piece and a diaphragm to obtain a dry battery cell; s2, mixing electrolyte, a polymerization monomer, an initiator and a redox shuttle agent to obtain a precursor of the in-situ curing electrolyte; s3, injecting a precursor of the in-situ curing electrolyte into a dry cell, and standing to obtain a battery to be cured; and S4, performing heat insulation treatment on the battery to be cured, and performing constant-current charging to enable the precursor of the in-situ curing electrolyte to be heated and cured, and performing formation and aging processes to obtain the in-situ solid-state battery.
  10. 10. The method of claim 9, wherein the method satisfies at least one of the following conditions (14) - (19): (14) The assembling mode in the step S1 comprises winding, lamination or hot-pressing compounding; (15) The mass ratio of the electrolyte to the polymerization monomer to the initiator to the redox shuttle agent in the step S2 is 55-95:1-35:0.1-1:0.1-10; (16) The standing time of the step S3 is 6-72h; (17) The self-balancing voltage of the constant current charging is 3.2-4.9V; (18) The self-balancing current of the constant current charge is 0.2-10A, or (19) The constant current charging time is 12-72h.

Description

In-situ solidified electrolyte, in-situ solid-state battery and preparation method of in-situ solid-state battery Technical Field The invention belongs to the technical field of batteries, and particularly relates to an in-situ solidified electrolyte, an in-situ solid-state battery and a preparation method thereof. Background The lithium battery is widely applied to the fields of electric automobiles, energy storage, 3C and the like due to the advantages of high energy density, high voltage platform, long cycle life and the like. Currently, improving the energy density and the safety of batteries is two major core development directions in the industry. The electrolyte represented by the carbonate organic solvent has been successful in commercial application, but is superior to the safety problems of easy leakage, easy volatilization, easy combustion and the like, so that the development of the solid electrolyte becomes urgent. The solid electrolyte not only can remarkably improve the safety of the battery, but also can be compatible with a lithium metal negative electrode, thereby greatly improving the energy density of the battery. The solid electrolyte is mainly classified into an inorganic solid electrolyte and a polymer solid electrolyte, the inorganic solid electrolyte has high ionic conductivity, a wide electrochemical window and excellent mechanical strength, however, the problems of insufficient interfacial stability between the electrode and the electrolyte, great processing difficulty, high cost and the like limit the further development thereof. Polymer solid electrolytes have received great attention in the industry due to their simple processing techniques and good interfacial compatibility. The polymer electrolyte is prepared ex-situ, and the electrolyte membrane prepared outside is used for assembling a battery, and the polymer electrolyte is only in contact with the surface of an electrode, so that the problem of loose contact exists, the utilization rate of active substances is low, and the cycle performance of the battery is poor. In-situ polymerization solid electrolyte is prepared by mixing a polymerization monomer, an initiator and electrolyte to form an electrolyte precursor solution, and in-situ initiating monomer molecule polymerization under certain external conditions (such as thermal initiation, photoinitiation and the like) to obtain the polymer electrolyte capable of conducting lithium ions. Because ultraviolet light and the like cannot penetrate through the outer shell such as an aluminum plastic film and the like, photoinitiation cannot be applied to in-situ polymerization of a battery cell level, so that thermal initiation is the most suitable polymerization mode. The battery is heated and polymerized mainly through a heat conduction mode by heat initiation, the outer side of the battery core is heated firstly, then heat is conducted to the inner part of the battery core, uneven distribution of heat fields inside and outside the battery core is caused, and the phenomenon that solidification is uneven easily caused by heat initiation is caused. The Chinese patent with publication number CN116404259A discloses a method for heating a battery cell filled with an in-situ cured electrolyte precursor by pulse current, and realizing uniform heating inside the battery cell by utilizing self impedance inside the battery, so that the polymerization effect is more uniform. However, this method requires additional pulse charge and discharge equipment, resulting in additional production costs. Chinese patent publication No. CN116093426a discloses a method for preparing an electropolymerized gel electrolyte battery, which does not require addition of an initiator, and avoids adverse effects of additional initiator on battery performance, but the surface of an electrode is coated with an electrochemically initiated polymerization product, and the conductivity of the polymerization product is poor, which may result in incomplete polymerization of subsequent monomers. Disclosure of Invention The invention provides an in-situ curing method, which improves the uniformity of in-situ cured electrolyte on the basis of simplifying the curing process and is a technical problem to be solved. In a first aspect of the present invention, there is provided a cured in place electrolyte comprising a polymerized monomer, an initiator, a redox shuttle and an electrolyte; The in-situ solidified electrolyte is prepared by constant-current charging-heating polymerization of the raw materials in a battery. The redox shuttle agent is introduced into the raw materials of the in-situ cured electrolyte and is treated by constant current charging, so that the redox shuttle agent can generate redox reaction under the specific self-balancing voltage in the charging process of the battery, continuously and stably convert electric energy into heat energy, and uniformly heat the precursor of the in-situ cured electrolyte,