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CN-121992399-A - Preparation method of fluorinated boron nitride coating for long-cycle stable battery cathode

CN121992399ACN 121992399 ACN121992399 ACN 121992399ACN-121992399-A

Abstract

The invention discloses a preparation method of a boron fluoride coating for a long-cycle stable battery cathode, which comprises the steps of mixing and grinding boron nitride and ammonium fluoride uniformly according to a certain proportion, adding a solvent according to a certain proportion, mixing uniformly, transferring to a reaction kettle for reaction, washing, centrifuging and drying a reaction product to obtain boron fluoride, mixing the boron fluoride with a binder, dripping an organic solvent, fully stirring to obtain a coating slurry, removing a passivation layer on the surface of a zinc foil, exposing unoxidized Zn, carrying out ultrasonic treatment on the treated zinc foil, drying, uniformly coating the coating slurry on the surface of the treated zinc foil, and carrying out vacuum drying to obtain the zinc foil containing the boron fluoride coating. The invention adopts the boron fluoride coating to protect the zinc cathode, inhibits hydrogen evolution reaction and zinc dendrite growth, and uniformly deposits zinc ions, so that the battery has better electrochemical long-term circularity.

Inventors

  • ZHANG WENJING
  • Sun shang
  • ZHANG NAN
  • FU YU
  • LI FAN
  • ZHOU MIN

Assignees

  • 青岛贝思仪新材料科技有限公司

Dates

Publication Date
20260508
Application Date
20241108

Claims (9)

  1. 1. The preparation method of the fluorinated boron nitride coating for the long-cycle stable battery cathode is characterized by comprising the following steps of: step S1, uniformly mixing and grinding boron nitride and ammonium fluoride according to a proportion, adding a solvent, uniformly mixing, transferring to a reaction kettle for reaction, and washing, centrifuging and drying a reaction product to obtain boron nitride fluoride; Step S2, mixing boron fluoride and a binder, then dripping an organic solvent, and fully stirring to obtain coating slurry for later use; step S3, removing the passivation layer on the surface of the zinc foil, and then carrying out ultrasonic treatment on the treated zinc foil and drying; and S4, uniformly coating the coating slurry obtained in the step S2 on the surface of the zinc foil treated in the step S3, and drying in vacuum to obtain the zinc foil containing the boron nitride fluoride coating.
  2. 2. The method according to claim 1, wherein in the step S1, the boron nitride is hexagonal boron nitride in a state of powder, and the ammonium fluoride is white crystalline powder.
  3. 3. The method according to claim 1, wherein in step S1, the reaction temperature of the reaction kettle is 150-300 ℃ and the reaction time is 12-36h.
  4. 4. The method of claim 1, wherein the reaction product washing in step S1 is performed by alternately washing with absolute ethanol and deionized water to neutrality.
  5. 5. The method according to claim 1, wherein the mass ratio of the fluorinated boron nitride to the binder in step S2 is 6:1-9:1.
  6. 6. The method according to claim 1, wherein in step S2, the stirring speed is 300-600rpm and the stirring time period is 2-8 hours.
  7. 7. The method according to claim 1, wherein in step S3, the zinc foil surface passivation layer is removed by means of sandpaper having a mesh size of 400-4000 mesh.
  8. 8. The method according to claim 1, wherein in step S4, the fluorinated boron nitride has a thickness in the range of 5-30 microns.
  9. 9. The method according to claim 1, wherein in step S4, the drying temperature of the vacuum drying is 40-80 ℃ and the drying time is 12-24 h.

Description

Preparation method of fluorinated boron nitride coating for long-cycle stable battery cathode Technical Field The invention belongs to the technical field of electrochemical energy storage, and particularly relates to a preparation method of a fluorinated boron nitride coating for a long-cycle stable battery cathode. Background In order to cope with global climate change and energy crisis, china strives to build a novel power system mainly based on new energy. Therefore, efficient conversion and storage of renewable energy is an important direction of current scientific research. The lithium ion battery has very important roles in the development process of the current age due to the characteristics of high energy density, high working voltage, chargeable property, mature commercialization development and the like. However, the unsafe issues of lithium ion batteries have hindered their development and use. In recent years, aqueous electrolyte batteries have been increasingly used as a popular means of research in the field of energy storage due to their excellent safety and high environmental friendliness, as compared with organic electrolyte batteries. Among the many aqueous multivalent metal ions, zinc metal has the advantages of (1) high theoretical capacity (820 mAh g-1), (2) suitable redox potential (-0.76V vs. she) in aqueous electrolyte, (3) abundant resources, and (4) lower polarization than metal materials such as Mg, al, etc. Thus, aqueous secondary zinc cells are considered to be a powerful competitor for next generation electrochemical energy storage systems. Although having many advantages, the aqueous zinc ion battery is expected to be used as a next-generation energy storage device. However, in practical applications, some reactions may affect the zinc deposition process, resulting in reduced efficiency of zinc stripping and further incomplete dissolution of zinc. Thus, some zinc gradually deposits unevenly on the surface of the zinc anode, forming needle-like zinc dendrites. The zinc dendrites continue to form and grow, eventually penetrating the separator, causing the cell to short circuit. In addition, after zinc dendrites are formed, their mechanical rigidity and uneven structure may cause them to fall off from the surface of the zinc anode, forming "dead zinc", resulting in a decrease in battery active material and a decrease in capacity. Phenomena that may also occur at the electrode/electrolyte interface include hydrogen evolution reactions, metal corrosion, and passivation. These phenomena are not independent but always interact, eventually leading to a deterioration of the coulombic efficiency, cyclic stability, reversibility and capacity reduction of the zinc-ion battery. Therefore, the stability of the zinc metal cathode/electrolyte interface of the water system zinc ion battery needs to be regulated and controlled, zinc dendrite, corrosion, hydrogen evolution reaction and the like are inhibited, and a safe and stable water system energy storage device is realized. Disclosure of Invention The invention mainly solves the technical problems of improving the interface stability of a zinc metal cathode/electrolyte of a water system zinc ion battery and solving the unsafe problem of the lithium ion battery. The invention provides a preparation method of a boron fluoride coating for a long-cycle stable battery cathode, which is characterized by comprising the following steps of S1, mixing and grinding boron nitride and ammonium fluoride uniformly according to a certain proportion, adding a solvent according to the proportion, mixing uniformly, transferring to a reaction kettle for reaction, and washing, centrifuging and drying a reaction product to obtain boron fluoride. And S2, mixing the boron fluoride with the binder, then dripping an organic solvent, and fully stirring to obtain the coating slurry. And S3, removing the passivation layer on the surface of the zinc foil, exposing unoxidized Zn, and carrying out ultrasonic treatment and drying on the treated zinc foil for later use. And S4, uniformly coating the coating slurry obtained in the step S2 on the surface of the zinc foil treated in the step S3, and carrying out vacuum drying to obtain the zinc foil containing the boron nitride fluoride coating. Preferably, in the step S1, the boron nitride is hexagonal boron nitride, the state is powder, and the ammonium fluoride state is white crystalline powder. Preferably, the reaction temperature of the reaction kettle in the step S1 is 150-300 ℃ and the reaction time is 12-36h. . Preferably, in step S1, the reaction product is washed by using absolute ethanol and deionized water alternately until the pH is neutral. Preferably, the mass ratio of the fluorinated boron nitride to the binder in the step S2 is 6:1-9:1. Preferably, the stirring speed in the step S2 is 300-600rpm, and the stirring time is 2-8 h. Preferably, in step S3, the passivation layer on the surface of the zinc foil is re