CN-121983502-A - Metal zinc anode with PDMS@MOF composite coating and preparation method thereof

Abstract

The invention discloses a metal zinc anode with a PDMS@MOF composite coating and a preparation method thereof, and belongs to the technical field of water-based zinc ion batteries. The technical scheme is that the negative electrode comprises a metal zinc negative electrode and a PDMS@MOF composite coating arranged on the surface of the metal zinc negative electrode, wherein the PDMS@MOF composite coating is a composite structure formed by penetrating and coating polydimethylsiloxane PDMS on the surface of a metal organic framework MOF. The invention has the beneficial effects that the PDMS@MOF composite structure coating is constructed on the negative electrode to cooperatively inhibit zinc dendrite growth and side reaction, so that the cycle life and stability of the battery are obviously improved.

Inventors

• GE MINGZHENG
• SHANG JING
• ZHAO YANRUI
• CAO CHUNYAN

Assignees

• 南通大学

Dates

Publication Date

20260505

Application Date

20251219

Claims (10)

1. 1. The metal zinc anode with the PDMS@MOF composite coating is characterized by comprising a metal zinc anode and the PDMS@MOF composite coating arranged on the surface of the metal zinc anode, wherein the PDMS@MOF composite coating is a composite structure formed by penetrating and coating polydimethylsiloxane PDMS into the surface and pores of a metal organic framework MOF.
2. 2. The metal zinc cathode according to claim 1, wherein the metal zinc cathode is zinc foil, and the thickness of the PDMS@MOF composite coating is 10-20 μm.
3. 3. A method for preparing the metallic zinc anode with the pdms@mof composite coating according to any one of claims 1 to 2, comprising the following steps: (1) Respectively dissolving metal salt and organic ligand in methanol to obtain two solutions, mixing the two solutions, stirring, standing, centrifugally collecting precipitate, washing and drying to obtain metal-organic framework MOF material; (2) Dissolving the MOF material obtained in the step (1) and a binder in the N-methyl pyrrolidone according to the mass ratio to form slurry, coating the slurry on the treated zinc foil, and drying to obtain the metal zinc anode with the MOF coating; (3) And (3) dissolving polydimethylsiloxane PDMS in tetrahydrofuran to form a solution, spraying the solution onto the metal zinc cathode with the MOF coating obtained in the step (2), and drying to obtain the metal zinc cathode with the PDMS@MOF composite coating.
4. 4. The method according to claim 3, wherein in the step (1), the metal salt is zinc nitrate hexahydrate or cobalt nitrate hexahydrate, and the organic ligand is 2-methylimidazole or 2-nitroimidazole.
5. 5. The method according to claim 4, wherein the molar ratio of the metal salt to the organic ligand is 2-5:1.
6. 6. The preparation method according to claim 3, wherein in the step (1), the washing is performed by alternately centrifuging with deionized water and ethanol for 3-5 times, and the drying is performed by vacuum drying at 60-80 ℃ for 12h.
7. 7. The method of claim 3, wherein in step (2), the mass ratio of the MOF material to the binder is 9:1, and the binder is polyvinylidene fluoride.
8. 8. The method according to claim 3, wherein in the step (2), the coating is performed by using a four-sided coater, the wet film thickness is 30 to 50. Mu.m, and the drying is vacuum-dried at 110 ℃ for 12 hours.
9. 9. The preparation method of the polymer film according to claim 3, wherein in the step (3), the volume ratio of the PDMS to the tetrahydrofuran is 1:2, a spray gun is used for spraying, the spraying distance is 5-15 cm, the time is 5-10 s, and the drying is carried out under vacuum at 110 ℃ for 18h.
10. 10. An aqueous zinc-ion battery comprising a metallic zinc anode having a pdms@mof composite coating as claimed in any one of claims 1-2.

Description

Metal zinc anode with PDMS@MOF composite coating and preparation method thereof Technical Field The invention belongs to the technical field of water-based zinc ion batteries, and particularly relates to a metal zinc anode with a PDMS@MOF composite coating and a preparation method thereof. Background With the widespread use of electronic devices, the performance requirements for secondary batteries are increasingly increasing. The most widely used lithium ion batteries in the world are now low in safety, but the lithium ion batteries are worried about the condition that the explosion of the batteries is caused by the easy leakage of electrolyte. Lithium ion batteries are currently the most commercialized secondary batteries, which have been widely used in various fields, but they have high costs and a certain risk. The water-based zinc ion battery is paid attention to by researchers because of the advantages of high content of metallic zinc in the crust, low cost, more proper oxidation-reduction potential (standard hydrogen electrode-0.76V vs), high theoretical capacity (820 mAh g -1 and 5855mAh cm -3) and the like. The aqueous zinc ion battery AZIB is generally a salt solution of water, and therefore has high safety. However, the water-based zinc ion battery also has some problems that in the deposition stripping cycle of the battery, zinc dendrite growth can cause serious harm to the battery, too long dendrite is easy to cause membrane puncture to cause short circuit of the battery, hydrogen evolution phenomenon occurs in the cycle process, extra hydrogen generated in the cycle process is easy to cause swelling of the battery, zinc cathode corrosion, occurrence of byproducts (basic zinc sulfate) and the like can also influence the overall performance of the battery, and the coulomb efficiency is reduced. The above problems have all seriously affected the performance of zinc ion batteries. Researchers have now proposed new electrolyte development and optimization strategies for negative electrode interface modification and separator design. The method comprises the steps of introducing tranexamic acid (TXA) as an additive into a ZnSO 4 electrolyte system, wherein TXA molecules are preferentially adsorbed on a zinc negative electrode interface, so that the negative electrode/electrolyte interface (AEI) is optimized, the TXA molecules can induce the preferential growth of Zn 2+ along a Zn (002) crystal face, the diffusion of two-dimensional Zn 2+ is limited, the formation of zinc dendrites is lightened, hydrophobic perfluoropolyether (PFPE) is simply coated on a zinc negative electrode by using Tao and the like, a hydrophobic protective coating is constructed, the diffusion of Zn 2+ is promoted, the direct contact of water molecules with the zinc negative electrode is effectively isolated, and the occurrence of side reactions is restrained. And a layer of ZnF 2 is formed on the zinc layer in situ, so that the circulation stability and reversibility are improved. However, the prior art has the limitations that although a single hydrophobic coating can block water to a certain extent, an ion transmission bottleneck may exist, so that polarization is increased, the regulation and control capability on zinc ion deposition behavior is limited, and the dendrite inhibition and side reaction inhibition are difficult to simultaneously combine. Therefore, the microcosmic action mechanism of the metal zinc cathode/electrolyte interface is deeply explored, and the development of a novel interface modification layer with adjustable characteristics has great significance in enhancing the interface stability and improving the long-cycle performance of the zinc ion battery. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a metal zinc anode with a PDMS@MOF composite coating and a preparation method thereof. The metal zinc cathode with the PDMS@MOF composite coating comprises a metal zinc cathode and the PDMS@MOF composite coating arranged on the surface of the metal zinc cathode, wherein the PDMS@MOF composite coating is a composite structure formed by permeation and cladding of polydimethylsiloxane PDMS into the surface and pores of a metal organic framework MOF. Further, the metal zinc cathode is zinc foil, and the thickness of the PDMS@MOF composite coating is 10-20 microns. The preparation method of the metal zinc anode with the PDMS@MOF composite coating comprises the following steps: (1) Respectively dissolving metal salt and organic ligand in methanol to obtain two solutions, mixing the two solutions, stirring, standing, centrifugally collecting precipitate, washing and drying to obtain metal-organic framework MOF material; (2) Dissolving the MOF material obtained in the step (1) and a binder in the N-methyl pyrrolidone according to the mass ratio to form slurry, coating the slurry on the treated zinc foil, and drying to obtain the metal zinc anode with the MOF coating; (3