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CN-122025799-A - High-voltage-resistant electrolyte, preparation method, application and potassium ion battery

CN122025799ACN 122025799 ACN122025799 ACN 122025799ACN-122025799-A

Abstract

The invention relates to a high-voltage-resistant electrolyte, a preparation method, application and a potassium ion battery, wherein the electrolyte comprises electrolyte potassium salt and an electrolyte solvent, and the electrolyte potassium salt is one or more of potassium hexafluorophosphate, potassium tetrafluoroborate, potassium difluorosulfimide, potassium trifluoromethane sulfonate, potassium bis (trifluoromethane) sulfimide, potassium nitrate and potassium perchlorate. The electrolyte provided by the invention has a simple manufacturing process, and has excellent oxidation stability, and the electrolyte is applied to a high-voltage potassium ion battery, so that stable electrode-electrolyte interface can be formed by virtue of preferential decomposition of more anions under the condition that cyclic carbonate is not added as a film forming cosolvent, and the compatibility of the carbonate-based electrolyte and the anode and the cathode of the potassium ion battery is improved.

Inventors

  • ZHU YUJIE
  • BAI YUE

Assignees

  • 北京航空航天大学

Dates

Publication Date
20260512
Application Date
20260311

Claims (10)

  1. 1. The electrolyte is characterized by comprising electrolyte potassium salt and electrolyte solvent, wherein the electrolyte potassium salt is one or more of potassium hexafluorophosphate, potassium tetrafluoroborate, potassium difluorosulfimide, potassium trifluoromethane sulfonate, potassium bis (trifluoromethane) sulfimide, potassium nitrate and potassium perchlorate.
  2. 2. The electrolyte of claim 1, wherein the electrolyte solvent is a chain carbonate, the chain carbonate being one or more of dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, di-n-butyl carbonate, dipentyl carbonate, dioctyl carbonate, methyl isopropyl carbonate, ethyl isobutyl carbonate, or diisopropyl carbonate.
  3. 3. A method for preparing the electrolyte of any one of claims 1-2, characterized in that the method is used for preparing the electrolyte of high pressure resistance, comprising: s1, weighing electrolyte potassium salt and chain carbonate according to a preset mass ratio; S2, dissolving electrolyte potassium salt in chain carbonate; s3, stirring the mixed system, and standing to obtain the chain carbonate-based electrolyte.
  4. 4. The method according to claim 3, wherein the predetermined mass ratio of the potassium salt to the chain carbonate is (10-40): 60-90.
  5. 5. Use of the high-voltage resistant electrolyte prepared by the preparation method of any one of claims 3 to 4 in a potassium ion battery.
  6. 6. A potassium-ion battery, characterized in that it comprises the electrolyte according to any one of claims 1-2.
  7. 7. The battery of claim 6, wherein the battery is a full cell or half cell.
  8. 8. A method for preparing a potassium ion battery, wherein the method is used for preparing the battery of any one of claims 6-7, comprising: (1) Preparing a positive electrode plate, namely taking Prussian blue analogues as a positive electrode active material, taking carbon nano tubes as conductive carbon and PVDF as a binder, fully and uniformly mixing the positive electrode active material, the carbon nano tubes and the binder PVDF according to a proportion, adding N-methylpyrrolidone (NMP), uniformly stirring to form slurry, uniformly coating on an aluminum foil current collector, and drying in a vacuum environment to obtain the positive electrode plate; (2) The half battery is prepared by using potassium metal as a counter electrode and glass fiber as a diaphragm, and assembling the cathode shell, the elastic sheet, the gasket, the potassium metal, the electrolyte, the diaphragm, the electrolyte, the anode plate and the anode shell in sequence.
  9. 9. The preparation method of the potassium ion battery is characterized by comprising the steps of (1) preparing a negative electrode plate, namely mixing a negative electrode active material and sodium carboxymethylcellulose in proportion, adding water, uniformly stirring to form slurry, uniformly coating the slurry on an aluminum foil current collector, and drying in a vacuum environment to obtain the negative electrode plate; (2) The half cell is prepared by using potassium metal as a counter electrode and glass fiber as a diaphragm, and assembling the cathode shell, the elastic sheet, the gasket, the potassium metal, the electrolyte, the diaphragm, the electrolyte, the cathode pole piece and the anode shell in sequence.
  10. 10. The preparation method of the potassium ion battery is characterized by comprising the steps of (1) preparing a positive electrode plate, namely using Prussian blue analogues as positive electrode active materials, using carbon nanotubes as conductive carbon and PVDF as a binder, mixing the positive electrode active materials, the carbon nanotubes and the binder PVDF in proportion, adding N-methylpyrrolidone (NMP), stirring uniformly to form slurry, uniformly coating on an aluminum foil current collector, and drying in a vacuum environment to obtain the positive electrode plate; (2) The preparation of the negative electrode plate comprises the steps of mixing a negative electrode active material and sodium carboxymethylcellulose in proportion, adding water, uniformly stirring to form slurry, uniformly coating the slurry on an aluminum foil current collector, and drying in a vacuum environment to obtain the negative electrode plate; (3) The preparation of the potassium ion battery comprises the steps of taking glass fiber as a diaphragm, and assembling the negative electrode shell, the elastic sheet, the gasket, the negative electrode plate, the electrolyte, the diaphragm, the electrolyte, the positive electrode plate and the positive electrode shell in sequence.

Description

High-voltage-resistant electrolyte, preparation method, application and potassium ion battery Technical Field The invention belongs to the technical field of potassium ion batteries, and particularly relates to a high-voltage-resistant electrolyte, a preparation method, application and a potassium ion battery. Background At present, the lithium ion battery has been widely applied in the fields of electronic equipment, electric automobiles and the like by virtue of the advantages of high energy density and long cycle life. However, lithium resources face the problems of strong scarcity, uneven distribution and large cost fluctuation, so that the lithium resources are difficult to meet the increasing demands of electrochemical energy storage systems for low cost. Under the background, the potassium ion battery becomes a potential lithium ion battery alternative scheme due to the characteristics of abundant reserves, low cost, lower standard electrode potential and the like. The practical application of potassium ion batteries places stringent requirements on the electrolyte. From the standpoint of constructing a practical battery with high energy density, the electrolyte needs to have sufficient stability for both the positive electrode and the negative electrode, namely, a stable and compact Solid Electrolyte Interface (SEI) needs to be constructed on the negative electrode side, and the electrolyte needs to meet corresponding performance requirements for matching the positive electrode material with high working voltage on the positive electrode side. The carbonate electrolyte is used as the electrolyte system which is most widely applied in commercial lithium ion batteries, has excellent oxidation stability, and can be adapted to a high-voltage positive electrode to realize stable work. The existing carbonate electrolyte mostly adopts a mixed system of cyclic carbonate and chain carbonate, wherein the cyclic carbonate is mainly used as a film forming cosolvent, and an SEI film is formed on the surface of an electrode through self-decomposition, so that the interface stability is ensured. Such electrolytes are subject to cyclic Ethylene Carbonate (EC) which forms a large SEI thickness and maldistribution, resulting in a higher interfacial impedance and slow charge transfer kinetics. In addition, EC has a high melting point (36.5 ℃) and a high viscosity, making it difficult for EC-containing electrolytes to meet low temperature application requirements. On the other hand, although the chain carbonate has a low melting point (-43 ℃) and viscosity, it cannot form a protective interface on the surface of the electrode-electrolyte, and it is difficult to maintain stable operation of the battery under extreme conditions such as high voltage, high and low temperature. Therefore, it is necessary to research a chain carbonate-based electrolyte, a preparation method, application and a potassium ion battery, which can cope with the prior art blank and realize the compatibility of the electrolyte and the anode and the cathode of the high-performance potassium ion battery. Disclosure of Invention In order to overcome the problems in the prior art, the invention provides a high-voltage-resistant electrolyte, a preparation method, application and a potassium ion battery, which are used for solving the problems in the prior art. The electrolyte comprises electrolyte potassium salt and electrolyte solvent, wherein the electrolyte potassium salt is one or more of potassium hexafluorophosphate, potassium tetrafluoroborate, potassium difluorosulfimide, potassium trifluoromethane sulfonate, potassium bis (trifluoromethane) sulfimide, potassium nitrate and potassium perchlorate. In aspects and any one of the possible implementations described above, there is further provided an implementation in which the electrolyte solvent is a chain carbonate, and the chain carbonate is one or more of dimethyl carbonate, methylethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, di-n-butyl carbonate, dipentyl carbonate, dioctyl carbonate, methyl isopropyl carbonate, ethyl isobutyl carbonate, or diisopropyl carbonate. The invention also provides a preparation method of the high-pressure-resistant electrolyte, which is used for preparing the electrolyte and comprises the following steps: s1, weighing electrolyte potassium salt and chain carbonate according to a preset mass ratio; S2, dissolving electrolyte potassium salt in chain carbonate; s3, stirring the mixed system, and standing to obtain the chain carbonate-based electrolyte. In the aspects and any possible implementation manner, there is further provided an implementation manner, wherein the preset mass ratio of the potassium salt to the chain carbonate is (10-40): 60-90. The invention also provides application of the high-voltage-resistant electrolyte in a potassium ion battery. The invention also provides a potassium ion battery, which