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CN-121553999-B - Preparation method of manganese-rich precursor for positive electrode material

CN121553999BCN 121553999 BCN121553999 BCN 121553999BCN-121553999-B

Abstract

The invention relates to the technical field of electrode materials, in particular to a preparation method of a manganese-rich precursor for a positive electrode material. According to the invention, firstly, nickel acetate tetrahydrate and manganese acetate tetrahydrate are used as metal sources, 3', 5' -biphenyl tetracarboxylic acid and 2-amino terephthalic acid are used as ligands, a manganese-nickel bimetal organic frame is synthesized, and manganese acetate tetrahydrate, nickel acetate tetrahydrate, cobalt acetate tetrahydrate and lithium acetate tetrahydrate are deposited on the surface of the manganese-nickel bimetal organic frame under the action of a main complexing agent and a auxiliary complexing agent, so that a manganese-rich precursor for the anode material is obtained. The lithium ion battery prepared by the manganese-rich precursor has higher coulombic efficiency and excellent cycle stability and rate capability.

Inventors

  • HU QILONG
  • LI YONG
  • LIU QI
  • WU KUICHEN

Assignees

  • 湖南双富新材料科技有限公司

Dates

Publication Date
20260505
Application Date
20260122

Claims (6)

  1. 1. The preparation method of the manganese-rich precursor for the positive electrode material is characterized by comprising the following steps of: (1) Adding nickel acetate tetrahydrate and manganese acetate tetrahydrate into absolute ethyl alcohol, stirring for 20-40min to obtain solution A, adding 3,3', 5' -biphenyl tetracarboxylic acid and 2-amino terephthalic acid into sodium hydroxide aqueous solution, stirring for 20-40min to obtain solution B, dripping solution B into solution A, stirring for 2-4h after dripping, transferring into a reaction kettle, performing hydrothermal reaction, washing, centrifuging, and vacuum drying to obtain a manganese-nickel bimetallic organic frame; (2) Dissolving manganese acetate tetrahydrate, nickel acetate tetrahydrate, cobalt acetate tetrahydrate and lithium acetate tetrahydrate in deionized water to obtain a metal salt solution; (3) Dissolving citric acid in a mixed solution of deionized water and ethylene glycol to obtain a main complexing agent; (4) Sodium pyrophosphate and polyvinyl alcohol are dissolved in deionized water to obtain a complexing agent; (5) Adding a manganese-nickel bimetal organic frame into a metal salt solution, performing ultrasonic dispersion for 20-40min, simultaneously dropwise adding a main complexing agent and an auxiliary complexing agent, heating to 75-85 ℃ after the dropwise adding is finished, stirring for 2-4h, washing, and performing vacuum drying to obtain a manganese-rich precursor for the anode material; The addition amount of the 2-amino terephthalic acid in the step (1) is 20% -30% of the total molar amount of the nickel acetate tetrahydrate and the manganese acetate tetrahydrate; in the step (2), the dosage ratio of manganese acetate tetrahydrate, nickel acetate tetrahydrate, cobalt acetate tetrahydrate, lithium acetate tetrahydrate and deionized water is 20-40mmol:10-60mmol:10-30mmol:100-200mmol:150-250 mL; the dosage ratio of citric acid, deionized water and glycol in the main complexing agent in the step (3) is 200-400 mmol/200-400 mL/50-150 mL; The dosage ratio of sodium pyrophosphate, polyvinyl alcohol and deionized water in the auxiliary complexing agent in the step (4) is 40-60mmol:3-8mmol:50-100mL; in the step (5), the weight ratio of the manganese-nickel bimetallic organic framework, the metal salt solution, the main complexing agent and the auxiliary complexing agent is 8-12:150-250:300-500:50-100.
  2. 2. The method for producing a manganese-rich precursor for a positive electrode material according to claim 1, wherein the molar ratio of nickel acetate tetrahydrate to manganese acetate tetrahydrate in step (1) is 1:3.
  3. 3. The method for preparing a manganese-rich precursor for a positive electrode material according to claim 1, wherein the addition amount of 3,3', 5' -biphenyltetracarboxylic acid in the step (1) is 30% -50% of the total molar amount of nickel acetate tetrahydrate and manganese acetate tetrahydrate.
  4. 4. The method for producing a manganese-rich precursor for a positive electrode material according to claim 1, wherein the concentration of the aqueous sodium hydroxide solution in the step (1) is 0.5 to 2mol/L.
  5. 5. The method for preparing a manganese-rich precursor for a positive electrode material according to claim 1, wherein the hydrothermal reaction in the step (1) is carried out at a temperature of 105-115 ℃ for a time of 10-15 hours.
  6. 6. The method for preparing a manganese-rich precursor for a positive electrode material according to claim 1, wherein the vacuum drying in the step (5) is performed at a temperature of 175-185 ℃ for a time of 20-28h.

Description

Preparation method of manganese-rich precursor for positive electrode material Technical Field The invention relates to the technical field of electrode materials, in particular to a preparation method of a manganese-rich precursor for a positive electrode material. Background With the wide application of lithium ion batteries in the fields of electric automobiles, energy storage devices and consumer electronics, the requirements on battery performance are also continuously improved. The positive electrode material is used as a core component of the lithium ion battery, and the performance of the positive electrode material directly determines the energy density, the multiplying power performance and the cycle life of the battery. In recent years, manganese-rich cathode materials have received attention because of their low cost, abundant resources, environmental friendliness, and high specific capacity. However, the conventional manganese-rich cathode material still has some problems in practical application, such as low initial discharge specific capacity, insufficient coulombic efficiency, poor rate capability, poor cycling stability and the like, which limit the application of the conventional manganese-rich cathode material in high-performance lithium ion batteries. In response to the above problems, researchers have optimized the microstructure and electrochemical properties of manganese-rich cathode materials by introducing functional precursor materials. For example, manganese-nickel bimetal organic frameworks (MOFs) are used as precursors, and the conductivity and electrochemical activity of the anode material can be remarkably improved due to the unique pore channel structure and the characteristic of uniform metal ion distribution. However, the single MOF precursor still has the problems of insufficient cycle stability, poor rate performance and the like in practical application. Therefore, further optimizing the composition and structure of the MOF precursor becomes critical to improving the performance of the manganese-rich cathode material. With the wide application of lithium ion batteries in the fields of electric automobiles, energy storage devices and consumer electronics, the requirements on battery performance are also continuously improved. The positive electrode material is used as a core component of the lithium ion battery, and the performance of the positive electrode material directly determines the energy density, the multiplying power performance and the cycle life of the battery. In recent years, manganese-rich cathode materials have received attention because of their low cost, abundant resources, environmental friendliness, and high specific capacity. However, the conventional manganese-rich cathode material still has some problems in practical application, such as low initial discharge specific capacity, insufficient coulombic efficiency, poor rate capability, poor cycling stability and the like, which limit the application of the conventional manganese-rich cathode material in high-performance lithium ion batteries. Disclosure of Invention In view of the above, the present invention aims to provide a method for preparing a manganese-rich precursor for a positive electrode material, so as to further optimize the composition and structure of the MOF precursor, and improve the cycle stability and rate capability of the lithium ion battery prepared by the method. Based on the above object, the invention provides a preparation method of a manganese-rich precursor for a positive electrode material, which comprises the following steps: (1) Adding nickel acetate tetrahydrate and manganese acetate tetrahydrate into absolute ethyl alcohol, stirring for 20-40min to obtain solution A, adding 3,3', 5' -biphenyl tetracarboxylic acid and 2-amino terephthalic acid into sodium hydroxide aqueous solution, stirring for 20-40min to obtain solution B, dripping solution B into solution A, stirring for 2-4h after dripping, transferring into a reaction kettle, performing hydrothermal reaction, washing, centrifuging, and vacuum drying to obtain a manganese-nickel bimetallic organic frame; (2) Dissolving manganese acetate tetrahydrate, nickel acetate tetrahydrate, cobalt acetate tetrahydrate and lithium acetate tetrahydrate in deionized water to obtain a metal salt solution; (3) Dissolving citric acid in a mixed solution of deionized water and ethylene glycol to obtain a main complexing agent; (4) Sodium pyrophosphate and polyvinyl alcohol are dissolved in deionized water to obtain a complexing agent; (5) Adding the manganese-nickel bimetal organic frame into a metal salt solution, performing ultrasonic dispersion for 20-40min, simultaneously dropwise adding a main complexing agent and an auxiliary complexing agent, heating to 75-85 ℃ after the dropwise adding is finished, stirring for 2-4h, washing, and performing vacuum drying to obtain the manganese-rich precursor for the anode material. Preferabl