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CN-115986253-B - Regenerated positive electrode active material and preparation method thereof

CN115986253BCN 115986253 BCN115986253 BCN 115986253BCN-115986253-B

Abstract

The application discloses a preparation method of a regenerated positive electrode active material, which comprises the steps of sequentially adding a waste lithium ion battery positive electrode material into an aqueous solution of 2-hydroxy propionic acid and/or aspartic acid and an aqueous solution of ascorbic acid and/or tyrosine for reaction. Filtering, removing slag, regulating mole ratio of valuable metal ions and M n+ in the leaching liquor, regulating pH value, heating, evaporating and concentrating to obtain gel substance, calcining the gel substance step by step, adding the gel substance into solution containing coating agent to make solvothermal reaction, drying and low-temp. sintering treatment so as to obtain the regenerated positive electrode active material. Wherein the valuable metal ions comprise Ni 2+ 、Co 2+ 、Mn 2+ 、Li + and M n+ , M is one or more of W, zr, al, B, sr, nb, ta, n is 2, 3, 5 or 6, and the coating agent comprises a coating precursor and a phosphorus compound. The application also provides a regenerated positive electrode active material.

Inventors

  • JIANG LONG
  • ZU GUOJING
  • WANG PENGFENG
  • WEI GUOZHEN
  • ZENG LEIYING

Assignees

  • 厦门厦钨新能源材料股份有限公司

Dates

Publication Date
20260505
Application Date
20230201

Claims (8)

  1. 1. A method for producing a regenerated positive electrode active material, comprising the steps of: adding the waste lithium ion battery anode material into an aqueous solution of 2-hydroxy propionic acid and/or aspartic acid to perform a first reaction; adding an aqueous solution of ascorbic acid and/or tyrosine into the system after the first reaction at a certain flow rate to perform a second reaction to obtain a black turbid liquid; Filtering the obtained black turbid liquid, and removing slag to obtain a leaching liquid rich in valuable metal ions; Adjusting the molar ratio of each valuable metal ion to M n+ in the leaching solution, adjusting the pH value, heating, evaporating and concentrating to form a gel substance; The gel-like substance is subjected to two-step calcination in an oxygen or air atmosphere to obtain a primary regenerated positive electrode active substance, wherein the temperature of the first-step calcination is 300-450 ℃, the retention time is 2-12 h, the heating rate is 1-10 ℃ per minute, the temperature of the second-step calcination is 550-900 ℃, the retention time is 1-15 h, and the heating rate is 5-20 ℃ per minute; The primary regenerated positive electrode active material is put into a solution containing a coating agent for solvothermal reaction, dried and sintered at a low temperature to obtain the regenerated positive electrode active material; The valuable metal ions comprise Ni 2+ 、Co 2+ 、Mn 2+ 、Li + and M n+ , M is one or more of W, zr, al, sr, nb, ta, n is 2, 3, 5 or 6, the coating agent comprises a coating precursor and a phosphorus compound, the coating precursor is one of tetraethoxysilane, silicon ethoxide, titanium tetraethoxide, titanium acetate, vanadium acetate, vanadyl triisopropoxide, vanadium ethoxide and vanadium tert-butoxide, and the phosphorus compound is one of triethyl phosphate, trimethyl phosphate, trialkyl phosphate and potassium dihydrogen phosphate.
  2. 2. The method of claim 1, wherein the regenerated positive electrode active material has a chemical formula Li k Ni x Co y Mn z M m O 2 ·sT 3 (PO 4 ) 4 , , wherein x: y: z: m= (0.10-0.85): (0.05-0.20): (0.10-0.35): (0.001-0.1), and x+y+z+m= 1,0.95≤k≤1.15, 0< s≤0.05, and t is one of Ti, si, V.
  3. 3. The preparation method of claim 1, wherein the chemical general formula of the waste lithium ion battery anode material is LiNi x Co y Mn z M m O 2 , wherein x, y, z are m= (0-1): (0.001-0.1), and x, y and z are not 0 at the same time.
  4. 4. The preparation method according to claim 1, wherein the ratio of the mass of the 2-hydroxypropionic acid and/or the aspartic acid to the mass of the positive electrode material of the waste lithium ion battery is (5-50): (50-95), the temperature of the first reaction is 30-70 ℃, the time is 0.1-1h, and the stirring speed is 200-600r/min.
  5. 5. The preparation method of claim 1, wherein the ratio of the mass of the ascorbic acid and/or the tyrosine to the mass of the anode material of the waste lithium ion battery is 5-500:1000, the temperature of the second reaction is 30-55 ℃, the time is 0.1-1h, and the stirring speed is 300-800r/min.
  6. 6. The method according to claim 1, wherein the pH is adjusted to 6.5 to 7.5 and the heating temperature is 40 to 90 ℃.
  7. 7. The preparation method according to claim 1, wherein the solvothermal reaction is carried out at a temperature of 100-300 ℃ for a total time of 4-8 hours; The solvothermal reaction comprises two stages, wherein the temperature ratio of the first stage to the second stage is 1 (1-2), and the retention time ratio of the first stage to the second stage is 1 (1-2); the temperature of the low-temperature sintering treatment is 300-450 ℃ and the time is 2-6h.
  8. 8. A regenerated positive electrode active material prepared by the preparation method according to any one of claims 1 to 7.

Description

Regenerated positive electrode active material and preparation method thereof Technical Field The application relates to the technical field of waste lithium ion battery anode material recovery, in particular to a regenerated anode active material and a preparation method thereof. Background The prior art method for recycling the anode material of the waste lithium ion battery mainly focuses on a wet process and mainly recycles Li, ni, co, mn elements in the wet process. The valuable metals in the anode material are transferred into the solution in the form of ions by acid leaching or alkaline leaching, and then the salts or oxides of nickel sulfate, cobalt sulfate, manganese sulfate, lithium carbonate, cobalt oxide, nickel oxide and the like are obtained by separation, purification and multi-step precipitation, but the recovery process is complex, the high-efficiency separation technology of each metal ion in the leached solution has great difficulty, poor separation index, complex process flow and high cost. In addition, the nickel cobalt lithium manganate positive electrode active material applied in the market at present is subjected to modification treatment, namely the material itself contains other modification elements such as Al, zr, B and the like, and the elements are usually removed as impurities in the recycling process due to the low content of the elements in an active material system, so that only Li, ni, co, mn elements are recycled, thereby causing resource waste and increasing the cost for subsequent treatment of the impurities. In summary, it is necessary to develop a simple and efficient regeneration method, which not only can recycle Li, ni, co, mn elements, but also can recycle and regenerate the modified elements in the recycled Li, ni, co, mn elements in one step, and can further ensure that the performance of the regenerated positive electrode active material is further improved. Disclosure of Invention In order to solve the problems, the present application provides a method for preparing a regenerated positive electrode active material. Another object of the present application is to provide a regenerated positive electrode active material prepared by the above-mentioned preparation method. The application provides a preparation method of a regenerated positive electrode active material, which comprises the following steps: Adding the waste lithium ion battery anode material into an aqueous solution of 2-hydroxy propionic acid and/or aspartic acid to perform a first reaction, adding an aqueous solution of ascorbic acid and/or tyrosine into a system after the first reaction at a certain flow rate to perform a second reaction to obtain a black turbid liquid, filtering the obtained black turbid liquid, removing slag to obtain a leaching solution rich in valuable metal ions, adjusting the mole ratio of each valuable metal ion to M n+ in the leaching solution, adjusting the pH value, heating, evaporating and concentrating to form gel-like substances, and calcining the gel-like substances step by step to obtain the primary regenerated anode active substance. And (3) putting the primary regenerated positive electrode active material into a solution containing a coating agent for solvothermal reaction, drying, and performing low-temperature sintering treatment to obtain the regenerated positive electrode active material. Wherein the valuable metal ions comprise Ni 2+、Co2+、Mn2+、Li+ and M n+, M is one or more of W, zr, al, B, sr, nb, ta, n is 2, 3, 5 or 6, and the coating agent comprises a coating precursor and a phosphorus compound. The application also provides a regenerated positive electrode active material prepared by the preparation method. Compared with the prior art, the preparation method provided by the application organically combines the recovery of the waste lithium ion battery anode material containing the modified element with the preparation of the anode active material, adopts a one-step sol-gel method to crosslink metal ions to regenerate a new anode active material, fully utilizes the modified element in the regeneration process to carry out doping modification on the regenerated anode active material, avoids the waste of the modified element, saves the subsequent dry doping link, shortens the flow, saves the cost, and realizes the doping modification purpose on the regenerated anode active material. The doped ions are uniformly distributed in the bulk phase of the positive electrode material, so that the doped elements are uniformly distributed, the positive electrode material is preferentially grown to a layered structure in a synthesized mode, and meanwhile, in the later period of the regeneration process, a solvothermal method is adopted to coat the primary regenerated positive electrode active material, so that the material structure is more stable, and the electrochemical performance of the positive electrode material can be effectively improved. Drawings Fig. 1 is