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CN-116364921-B - Sodium ion battery anode material and preparation method and application thereof

CN116364921BCN 116364921 BCN116364921 BCN 116364921BCN-116364921-B

Abstract

The application provides a sodium ion battery anode material and a preparation method and application thereof, wherein the sodium ion battery anode material comprises an active material and a hydrophobic coating layer, a coating source of the hydrophobic coating layer comprises a siloxane-based compound, the siloxane-based compound is used as a coating source of the hydrophobic coating layer, a compound containing-Si-O-Na is generated on the surface of the active material, the hydrophobic property and the environmental stability can be ensured, and meanwhile, the sodium ion battery anode material has high ion conductivity, so that the obtained sodium ion battery has good cycle performance, and meanwhile, the sodium ion battery anode material is coated by adopting a molecular self-assembly method, so that the thickness change caused by the shape change of the material is avoided, and the technology requirement is low and the cost is low.

Inventors

  • DONG QINGYU
  • SHEN YANBIN
  • CHEN LIWEI

Assignees

  • 中国科学院苏州纳米技术与纳米仿生研究所

Dates

Publication Date
20260508
Application Date
20221208
Priority Date
20211229

Claims (17)

  1. 1. A sodium ion battery positive electrode material, characterized in that the sodium ion battery positive electrode material comprises an active material and a hydrophobic coating layer formed by molecular self-assembly, wherein a coating source of the hydrophobic coating layer comprises a siloxane-based compound; The siloxane group of the siloxane-based compound faces the active material and reacts with the active material to generate a compound containing-Si-O-Na; the hydrophobic end of the siloxane-based compound faces the outside air at the other end; The siloxane-based compound comprises any one or a combination of at least two of heptadecafluorodecyl trimethoxysilane, heptadecafluorodecyl triethoxysilane, pentadecafluorononyl trimethoxysilane, pentadecafluorononyl triethoxysilane, tridedecafluorooctyl trimethoxysilane or tridedecafluorooctyl triethoxysilane.
  2. 2. The positive electrode material of a sodium ion battery according to claim 1, wherein the thickness of the hydrophobic coating layer is 1-20 nm.
  3. 3. The positive electrode material for sodium ion battery according to claim 1, wherein the average particle diameter of the active material is 1 to 3 μm.
  4. 4. The sodium ion battery cathode material of claim 1, wherein the active material comprises NaNi 0.33 Fe 0.33 Mn 0.33 O 2 and/or NaCo 0.7 Mn 0.3 O 2 .
  5. 5. A method for preparing the positive electrode material of a sodium ion battery according to any one of claims 1 to 4, comprising the steps of: and coating the active material with a siloxane-based compound by adopting a liquid phase method or a gas phase method to obtain the sodium ion battery anode material.
  6. 6. The preparation method according to claim 5, wherein the mass ratio of the active material to the siloxane-based compound is 1 (0.02-0.08).
  7. 7. The method of claim 5, wherein the liquid phase process comprises mixing a solution of the active material and the siloxane-based compound, suction filtering, and drying.
  8. 8. The method according to claim 7, wherein the stirring speed of the mixing is 400-600 r/min.
  9. 9. The method according to claim 7, wherein the mixing time is 8 to 12 hours.
  10. 10. The method according to claim 7, wherein the temperature of the drying is 70-90 ℃ and the time is 0.8-1.2 hours.
  11. 11. The preparation method according to claim 7, wherein the solution of the siloxane-based compound comprises a siloxane-based compound and a solvent in a mass ratio of 1 (90-110).
  12. 12. The method of claim 11, wherein the solvent comprises any one or a combination of at least two of N-methylpyrrolidone, ethanol, N-dimethylformamide, tetrahydrofuran, or acetone.
  13. 13. The method of claim 5, wherein the vapor phase process comprises heating the siloxane-based compound, placing the active material in the vapor of the siloxane-based compound, cooling, stirring the active material, completing one coating, and repeating the coating 2-4 times.
  14. 14. The method of claim 13, wherein the heating of the siloxane-based compound is at a temperature of 80-100 ℃.
  15. 15. The method of claim 13, wherein the active material is placed in the vapor of the siloxane-based compound for a period of 5 to 7 hours.
  16. 16. The preparation method according to claim 5, characterized in that the preparation method comprises the steps of: The active material is coated by a liquid phase method or a gas phase method; the liquid phase method comprises the steps of mixing an active material with a solution of a siloxane-based compound for 8-12 hours at a stirring speed of 400-600 r/min, carrying out suction filtration, and drying at 70-90 ℃ for 0.8-1.2 hours to obtain the sodium ion battery anode material; The gas phase method comprises the steps of heating a siloxane-based compound at 80-100 ℃, placing an active material in steam of the siloxane-based compound for 5-7 hours, cooling, stirring the active material, finishing one-time coating, and repeatedly coating for 2-4 times to obtain the sodium ion battery anode material.
  17. 17. A sodium ion battery, characterized in that the sodium ion battery comprises the sodium ion battery positive electrode material according to any one of claims 1 to 4.

Description

Sodium ion battery anode material and preparation method and application thereof Technical Field The invention belongs to the technical field of sodium ion batteries, and relates to a positive electrode material, in particular to a sodium ion battery positive electrode material, a preparation method and application thereof. Background The secondary battery comprises a lithium ion battery, a sodium ion battery and the like, and is a high-energy-density secondary battery with great development potential and application prospect. Currently, sodium ion batteries, which are limited by Li resource starvation, raw material abundance and low cost, are receiving extensive attention from developers. Although the sodium ion battery positive electrode material is low in cost, the sodium ion battery is high in processing cost due to poor environmental stability in the storage and processing processes. Therefore, there is an urgent need to solve the problem of environmental stability of the positive electrode material of the sodium ion battery, and reduce the production cost of the sodium ion battery. CN 108987708A discloses a sodium ion battery positive electrode material, a preparation method thereof and a sodium ion battery, wherein the provided sodium ion battery positive electrode material comprises a matrix and a coating layer coated on the surface of the matrix, the chemical formula of the matrix is Na 0.67Ni0.167Co0.167Mn0.67O2, the coating layer is a ZrO layer, the mass of the coating layer in the sodium ion battery positive electrode material is 1-10% of the mass of the matrix, the preparation method comprises the steps of mixing a salt solution with an alkali solution, carrying out a reaction, carrying out solid-liquid separation to obtain carbonate of nickel, cobalt and manganese, presintering the carbonate of nickel, cobalt and manganese to obtain ternary nickel, cobalt and manganese oxide, mixing the ternary nickel, cobalt and manganese oxide with a sodium source, calcining to obtain the matrix, mixing the matrix with a zirconium source, and calcining to obtain the sodium ion battery positive electrode material, namely, the disclosed sodium ion positive electrode material is coated by adopting a high-temperature sintering solid-phase method, the coating is uneven, the coating layer is too thick, the ion conductivity is lower, the technological cost is higher, and the environmental stability is low. CN 108923042a discloses a layered manganese-based positive electrode material of a sodium ion battery and a preparation method thereof, wherein the general formula of the positive electrode material is Na yMn3-xMxO7, M is Cu, x is more than or equal to 0.1 and less than or equal to 2, y is more than or equal to 0 and less than or equal to 4, the positive electrode material has a triclinic crystal structure, and the surface of the positive electrode material is an oxide protection layer of sodium alkyne, and the disclosed layered manganese-based material of the sodium ion battery has a triclinic crystal structure and has the structural characteristic without phase change in a wide voltage range, so that the structural stability of the layered manganese-based positive electrode material in the charge-discharge process and the stability of the positive electrode material in the air exposure process can be effectively improved. Based on the above study, how to provide a positive electrode material of a sodium ion battery, which has a uniform and thinner coating layer, has higher stability in the environment, has hydrophobicity and high sodium ion conductivity, has a simple preparation method, can improve the cycle performance and capacity of the sodium ion battery, and becomes the problem which needs to be solved urgently at present. Disclosure of Invention The invention aims to provide a sodium ion battery anode material, a preparation method and application thereof, wherein the sodium ion battery anode material is provided with a hydrophobic coating layer, the hydrophobic coating layer is provided with high ion conductivity, strong hydrophobic capacity and good environmental stability, and the coated anode material shows good electrochemical performance in sodium ion battery application, In order to achieve the aim of the invention, the invention adopts the following technical scheme: In a first aspect, the present invention provides a sodium ion battery positive electrode material comprising an active material and a hydrophobic coating layer, the coating source of the hydrophobic coating layer comprising a siloxane-based compound. According to the invention, a siloxane-based compound is used as a coating source of the hydrophobic coating layer, a layer of hydrophobic film is provided on the surface of the active material, so that capacity loss caused by the reaction of the positive electrode material of the sodium ion battery with water and carbon dioxide in the environment is prevented, the coated active material