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CN-121626985-B - Waste graphite repairing material, preparation method and application thereof and lithium secondary battery

CN121626985BCN 121626985 BCN121626985 BCN 121626985BCN-121626985-B

Abstract

The invention belongs to the field of waste graphite material recovery, and in particular relates to a waste graphite repair material, a preparation method and application thereof, and a lithium secondary battery, wherein the preparation method comprises the steps of separating waste graphite from a waste lithium ion battery; the method comprises the steps of carrying out first-stage modification treatment on waste graphite in a polyphenol monomer solution in advance, wherein the polyphenol monomer is an organic matter containing 2-15 phenolic hydroxyl groups and having 6-20 carbon atoms, a positive electrode active material in a waste lithium ion battery comprises at least one transition metal element of nickel, cobalt, manganese and iron, adding a primary amine monomer and a phosphorus-containing auxiliary agent into a first-stage modification treatment system, carrying out phenolic amine copolymerization to obtain a graphite@phenolic amine copolymer, roasting the graphite@phenolic amine copolymer at the temperature of 500-700 ℃, and carrying out acid treatment, washing and drying treatment to obtain the waste graphite repairing material. The method can improve the multiplying power, low temperature and long cycle performance of the waste graphite repairing material.

Inventors

  • TANG JINGJING
  • YANG JUAN
  • SUN YUBO
  • YU RIQUAN
  • ZHOU XIANGYANG

Assignees

  • 中南大学

Dates

Publication Date
20260508
Application Date
20260204

Claims (10)

  1. 1. The preparation method of the waste graphite repair material is characterized by comprising the following steps: Step 1: The method comprises the steps of separating waste graphite from a waste lithium ion battery, carrying out first-stage modification treatment on the waste graphite in a solution of polyphenol monomers in advance, wherein positive electrode active materials in the waste lithium ion battery comprise at least one transition metal element of nickel, cobalt, manganese and iron, and the polyphenol monomers comprise at least one of tea polyphenol, protocatechuic acid, ellagic acid, chlorogenic acid, catechol and hydroquinone; the weight ratio of the waste graphite to the polyphenol monomer is 1:0.05-0.15; Step 2: Adding primary amine monomers and phosphorus-containing auxiliary agents into the first-stage modified system, and carrying out phenolic amine copolymerization to obtain a graphite@phenolic amine copolymer, wherein in the phenolic amine copolymerization process, the pH of the system is controlled to be 7.5-9.0, and the temperature is controlled to be 60-100 ℃; the primary amine monomer comprises one or more of urea, melamine, ethylenediamine, hexamethylenediamine, dicyandiamide, amino acid, 4-aminotrianiline, diaminoguanidine hydrochloride and amino-functionalized hexaazatriphenylene; the phosphorus-containing auxiliary agent comprises one or more of sodium hypophosphite, hypophosphorous acid, red phosphorus, ammonium dihydrogen phosphate, phosphoric acid, phytic acid, phenylphosphonic acid, triethyl phosphate, hexachlorocyclotriphosphazene and ammonium polyphosphate; The weight ratio of the primary amine monomer to the polyphenol monomer is 1:0.1-2; the phosphorus auxiliary agent accounts for 0.5-5% of the weight of the waste graphite; Step 3: roasting the graphite@phenol amine copolymer at the temperature of 500-700 ℃, and then carrying out acid treatment, washing and drying treatment to obtain the waste graphite repair material.
  2. 2. The method for preparing a waste graphite repair material according to claim 1, wherein the positive electrode active material in the waste lithium ion battery comprises at least one of NCM and NCA; In the waste graphite, the content of graphite is more than 90 wt.%.
  3. 3. The method for preparing a waste graphite repair material according to claim 1, wherein the pH value in the first stage modification process is 4.5-5.5; the temperature of the first stage modification process is 50-70 ℃.
  4. 4. The method for preparing a waste graphite repair material according to claim 3, wherein the polyphenol monomers further comprise auxiliary polyphenol monomers including at least one of tannic acid and quercetin; the content of the auxiliary polyphenol monomer in the polyphenol monomer is 5-30%.
  5. 5. The method for preparing the waste graphite repair material according to claim 1, wherein the primary amine monomer comprises melamine and diaminoguanidine hydrochloride in a ratio of 1-9:1-9; the phosphorus auxiliary agent is hexachlorocyclotriphosphazene.
  6. 6. The method for preparing the waste graphite repair material according to claim 1, wherein the weight ratio of the primary amine monomer to the polyphenol monomer is 1:0.5-1.5; The phosphorus auxiliary agent accounts for 0.8-2.5% of the weight of the waste graphite; the temperature in the phenol-amine copolymerization process is 80-95 ℃, and the time for phenol-amine copolymerization is 1-5 h.
  7. 7. The method for preparing a waste graphite repair material according to claim 1, wherein in the step 3, the atmosphere in the baking process is at least one of nitrogen and rare gas; the atmosphere in the roasting process also contains 1-5v% of hydrogen.
  8. 8. A waste graphite repair material produced by the production method of any one of claims 1 to 7.
  9. 9. The use of the waste graphite repair material according to claim 8 as a negative electrode active material for preparing a lithium secondary battery.
  10. 10. A lithium secondary battery, wherein the negative electrode comprises the waste graphite repair material according to claim 8.

Description

Waste graphite repairing material, preparation method and application thereof and lithium secondary battery Technical Field The invention relates to the technical field of lithium ion battery recovery, in particular to the field of waste graphite restoration and regeneration. Background With the popularization of electric automobiles, a large number of retired lithium ion batteries are in urgent need of treatment. The regeneration of graphite cathode from waste battery is key to reduce battery cost and realize resource closed loop. The conventional graphite regeneration means mainly adopts schemes of high-temperature calcination, acid purification and the like. For example, patent document publication No. CN120987314A discloses a method for regenerating waste graphite, a regenerated graphite negative electrode material and a secondary battery, wherein the method for regenerating waste graphite comprises roasting waste graphite slag, oxidizing and roasting to obtain roasted graphite, shaping and grading the roasted graphite to obtain shaped graphite, graphitizing the shaped graphite to obtain coarse graphite, removing impurities from the coarse graphite, and removing impurities from the coarse graphite. For another example, patent document CN117895122a discloses a method for regenerating a waste graphite negative electrode, which comprises the steps of calcining waste graphite powder, removing impurities by acid washing, retaining lithium in the graphite to obtain pretreated lithium-containing graphite, performing high-energy ball milling treatment on the pretreated lithium-containing graphite to obtain the pre-lithium graphite, mixing the pre-lithium graphite with a reconstruction agent, performing structural reconfiguration by adopting hot isostatic pressing treatment, calcining the graphite, crushing, and performing particle size classification to obtain regenerated pre-lithiated graphite. For another example, patent document CN115051062a discloses a method for directly regenerating waste graphite by using a eutectic solvent, which comprises the steps of (1) discharging, crushing and physically sorting a waste lithium ion battery to obtain waste graphite material in the waste lithium battery, (2) preparing the eutectic solvent, leaching the waste graphite material obtained in the step (1) with the eutectic solvent, and then centrifuging, cleaning, filtering and drying to obtain regenerated graphite, and (3) preparing the graphite electrode by using the regenerated graphite obtained in the step (2) as a raw material. In summary, the existing graphite regeneration method mainly comprises the schemes of high-temperature calcination, acid washing and the like, and generally faces two major bottlenecks, namely high energy consumption in the repairing process, only partial structure recovery and difficulty in solving the problem of interface deterioration, and secondly low initial coulombic efficiency, poor multiplying power performance and low-temperature performance of the regenerated graphite caused by the reconstruction and residual defects of a surface Solid Electrolyte Interface (SEI) film, which are difficult to directly use in a high-performance battery. Disclosure of Invention Aiming at the problems existing in the prior art, the first aim of the invention is to provide a preparation method of waste graphite repairing material, which aims at obtaining a regenerated graphite material with high first efficiency, quick charge, low temperature and long cycle stability based on waste graphite regeneration. The second aim of the invention is to provide the waste graphite repairing material prepared by the preparation method and the application thereof. A third object of the present invention is to provide a lithium secondary battery comprising the waste graphite repair material. A preparation method of waste graphite repair material comprises the following steps: Step 1: The method comprises the steps of separating waste graphite from a waste lithium ion battery, carrying out first-stage modification treatment on the waste graphite in a solution of a polyphenol monomer, wherein the polyphenol monomer is an organic matter containing 2-15 phenolic hydroxyl groups and having 6-20 carbon atoms, and the positive electrode active material in the waste lithium ion battery comprises at least one transition metal element of nickel, cobalt, manganese and iron; Step 2: adding primary amine monomer and phosphorus-containing auxiliary agent into the system of the first stage modification treatment, and carrying out phenolic amine copolymerization (also called as the second stage modification treatment) to obtain graphite@phenolic amine copolymer (also called as a second stage modification material), wherein in the phenolic amine copolymerization process, the pH of the system is controlled to be 7.5-9.0, and the temperature is controlled to be 60-100 ℃; The primary amine monomer is an organic matter containing 2-10 amino