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CN-122000450-A - Fluorine-nitrogen double-doped carbon quantum dot mediated in-situ crosslinking solid electrolyte material and preparation method thereof

CN122000450ACN 122000450 ACN122000450 ACN 122000450ACN-122000450-A

Abstract

The invention relates to a fluorine-nitrogen double-doped carbon quantum dot mediated in-situ crosslinking solid electrolyte material and a preparation method thereof. A preparation method of a fluorine-nitrogen double-doped carbon quantum dot mediated in-situ crosslinking solid electrolyte material comprises (1) preparing fluorine-nitrogen double-doped carbon quantum dots through aldehyde-amine condensation reaction, (2) carrying out Huffman alkylation reaction on an acrylic chloride monomer and the fluorine-nitrogen double-doped carbon quantum dots to obtain carbon quantum dots with surface grafted acrylamide functional groups, and (3) carrying out in-situ polymerization reaction on the carbon quantum dots with surface grafted acrylamide functional groups, lithium salt and a crosslinking agent containing double bonds to obtain the fluorine-nitrogen double-doped carbon quantum dot mediated in-situ crosslinking solid electrolyte material. According to the fluorine-nitrogen double-doped carbon quantum dot mediated in-situ crosslinking solid electrolyte material and the preparation method thereof, provided by the invention, a three-dimensional framework with a network structure is obtained by taking fluorine-nitrogen double-doped carbon quantum dot crosslinking nodes and a double-bond crosslinking agent as a three-dimensional framework.

Inventors

  • LI NANA
  • SHEN YANBING
  • ZHANG XIAOKANG
  • LIU PING
  • XU KELIANG

Assignees

  • 石河子大学

Dates

Publication Date
20260508
Application Date
20260203

Claims (10)

  1. 1. The preparation method of the fluorine-nitrogen double-doped carbon quantum dot mediated in-situ crosslinking solid electrolyte material is characterized by comprising the following steps of: (1) Preparing fluorine-nitrogen double-doped carbon quantum dots through aldehyde-amine condensation reaction; (2) Carrying out Huffman alkylation reaction on an acyl chloride monomer and the fluorine-nitrogen double-doped carbon quantum dot to obtain a carbon quantum dot with a double-bond functional group on the surface; (3) And carrying out in-situ polymerization reaction on the carbon quantum dots with double bond functional groups on the surfaces, lithium salt and a cross-linking agent with double bonds to obtain the fluorine-nitrogen double-doped carbon quantum dot mediated in-situ cross-linked solid electrolyte material.
  2. 2. The method according to claim 1, wherein, In the step (1), the process of preparing the fluorine-nitrogen double-doped carbon quantum dots by aldehyde-amine condensation reaction comprises the steps of adding fluorine-containing benzaldehyde and ethylenediamine into a solvent, adjusting the pH to 6-8, and carrying out water separation after hydrothermal reaction.
  3. 3. The method according to claim 2, wherein, The fluorine-containing benzaldehyde is one of 3-fluorobenzaldehyde, 3, 4-difluorobenzaldehyde, 2,4, 6-trifluorobenzaldehyde, 4-fluorobenzaldehyde, 2-fluorobenzaldehyde, 4-trifluoromethyl benzaldehyde and 4- (1, 1-difluoroethyl) benzaldehyde; The acid solution is one of acetic acid, citric acid, nitric acid, sulfuric acid and hydrochloric acid The molar ratio of the fluorobenzaldehyde to the ethylenediamine is 3-1:1; The solvent is one of methanol, ethanol and toluene; the hydrothermal reaction temperature is 80-180 ℃ and the time is 8-12h.
  4. 4. The method according to claim 1, wherein, In the step (2), the acyl chloride monomer is one of 2-fluoro-acryl chloride monomer, acryl chloride, methacryl chloride, (E) -2-methyl-2-butenoyl chloride and 4-pentenoyl chloride; in the Huffman alkylation reaction, the solvent is methylene dichloride, the catalyst is potassium carbonate, cesium carbonate or triethylamine solution, and the reaction is carried out for 5 to 12 hours at room temperature.
  5. 5. The method according to claim 1, wherein, In the step (3), the in-situ polymerization reaction is carried out by dissolving lithium salt in a cross-linking agent containing double bonds, adding into the carbon quantum dots with double bond functional groups on the surface, and carrying out in-situ polymerization reaction at 50-80 ℃ by taking azodiisobutyronitrile as an initiator.
  6. 6. The method according to claim 5, wherein, The lithium salt is one of lithium hexafluorophosphate, lithium perchlorate, lithium bis (trifluoromethanesulfonyl) imide and lithium bis (fluorosulfonyl) imide; The cross-linking agent containing double bonds is one of polyethylene glycol diacrylate, 2, 3-tetrafluoropropyl methacrylate, neopentyl glycol diacrylate, polyethylene glycol dimethacrylate and isobornyl acrylate.
  7. 7. The method according to claim 5, wherein, The lithium salt and the cross-linking agent containing double bonds form a mixed solution of 1-2 mol/L; The dosage of the carbon quanta with double bond functional groups on the surface is 10-30wt% of the total dosage of the lithium salt and the cross-linking agent with double bonds; The amount of the initiator Azodiisobutyronitrile (AIBN) is 0.5-2 wt% of the total mass of the cross-linking agent containing double bonds, lithium salt and carbon quantum dots with double bond functional groups on the surfaces.
  8. 8. A fluorine-nitrogen double-doped carbon quantum dot mediated in-situ crosslinking solid electrolyte material, which is characterized by being prepared by the preparation method of any one of claims 1-7.
  9. 9. A polymer solid state battery comprising the fluorine-nitrogen double doped carbon quantum dot mediated in situ cross-linked solid state electrolyte material of claim 8.
  10. 10. The polymer solid-state battery according to claim 9, wherein the fluorine-nitrogen double-doped carbon quantum dot-mediated in-situ cross-linked solid electrolyte material is provided with a positive electrode material and a negative electrode active material on both sides thereof; Wherein the positive electrode material is one or more of LiNi x Co y M 1-x-y O 2 、LiCoO 2 、LiMn 2 O 4 、LiFePO 4 , M in LiNi x Co y M 1-x-y O 2 is Mn or Al,0.2< x <0.9,0.1< y <0.5; the negative electrode active material is metallic lithium, lithium alloy, carbon series material, si-containing carbon series material or olivine structure transition metal material.

Description

Fluorine-nitrogen double-doped carbon quantum dot mediated in-situ crosslinking solid electrolyte material and preparation method thereof Technical Field The invention belongs to the technical field of solid electrolyte materials, and particularly relates to a fluorine-nitrogen double-doped carbon quantum dot mediated in-situ crosslinking solid electrolyte material and a preparation method thereof. Background With the increasing demand for high energy density and high safety batteries for electric vehicles and energy storage systems, solid state batteries are widely recognized as an important development direction for next generation energy storage technologies due to their potentially high energy density and excellent safety performance. Among them, the solid polymer electrolyte (Solid Polymer Electrolytes, SPEs) prepared by in-situ polymerization becomes an important technological path for realizing high-performance solid-state batteries due to its good interface contact property and processing adaptability. However, the existing SPE materials still face a plurality of key technical challenges, mainly including problems of low ionic conductivity, limited electrochemical stability window, poor interface compatibility with lithium metal negative electrode and high-voltage positive electrode, and the like, so that the commercialized application process of the materials is severely restricted. To enhance the overall performance of SPEs, researchers have proposed a variety of modification strategies including the introduction of inorganic fillers (e.g., LLZO, LLTO, NASICON ceramics,Etc.), interfacial engineering, surface modification, in situ synthesis of regulatory structures, synergistic use of plasticizers and fillers, etc. Although the above strategy improves the ionic conductivity and interface stability of SPE to a certain extent, there is still a need to solve the problems that on one hand, inorganic fillers are easy to agglomerate under high addition amount, so that local stress concentration and discontinuous ion transmission channels are caused, on the other hand, interface impedance is increased, overall ionic conductivity is reduced, on the other hand, the thermodynamic compatibility of the interface between a polymer matrix and the inorganic fillers is poor, and on the other hand, phenomena such as interface stripping, structural degradation and the like are easy to occur under long-term circulation or high-temperature conditions, so that the circulation stability and safety of a battery are influenced. In recent years, carbon quantum dots (Carbon Quantum Dots, CQDs) have wide application prospects in the field of solid electrolytes due to the unique structural characteristics and surface chemical adjustability. Researches show that the CQDs not only can be used as a construction unit of an ion conductive network to improve the migration efficiency of lithium ions, but also can be used as an interface stabilizer to improve the interface compatibility between organic and inorganic phases and enhance the structural stability of electrolyte. For example, oxygen-containing functional group modified CQDs may promote dissociation of lithium salts and selective adsorption of anions while reducing the crystallinity of the polymer matrix, thereby enhancing ionic conductivity. In addition, CQDs-induced supermolecular physical crosslinking strategies have also been demonstrated to effectively reduce the lithium ion transport energy barrier, achieving high ionic conductivity at room temperature. Although some progress has been made in SPE research based on CQDs, there are still many unsolved problems in terms of structure regulation, interface stability and performance synergistic mechanism, and it is highly required to establish a quantitative relationship between a filler structure and interface-performance through synergistic optimization of material design and interface engineering so as to promote practical application in all-solid-state lithium batteries. In view of this, the present invention provides a new solid electrolyte material and a preparation method thereof, which is an in-situ cross-linked solid electrolyte material mediated by fluorine-nitrogen double-doped carbon quantum dots, and is an in-situ composite high-performance solid electrolyte material. Disclosure of Invention The invention aims to provide a preparation method of a fluorine-nitrogen double-doped carbon quantum dot mediated in-situ crosslinking solid electrolyte material, which is characterized in that the fluorine-nitrogen double-doped carbon quantum dot modified by an amide group is subjected to double bond free radical polymerization reaction and a crosslinking agent containing double bonds to construct a novel three-dimensional continuous framework type electrolyte material taking the carbon quantum dot as an intermediate node and taking the crosslinking agent as a 'dot-chain' of a polymer chain. In order to achieve the above