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CN-116544410-B - Metal phosphate oligomer surface-coated layered structure positive electrode material, and preparation method and application thereof

CN116544410BCN 116544410 BCN116544410 BCN 116544410BCN-116544410-B

Abstract

The invention relates to a metal phosphate oligomer surface-coated layered structure anode material, and a preparation method and application thereof. The layered structure positive electrode material coated on the surface of the metal phosphate oligomer comprises a layered structure positive electrode material, wherein the inner part of the layered structure positive electrode material is provided with the metal phosphate oligomer, the surface of the layered structure positive electrode material is provided with a structural general formula LiXO 2 , X is at least one of Co, mn and Ni, the metal phosphate oligomer contains metal ions and phosphoric acid anions, the structural general formula is M x (PO 4 ) y , M is at least one of Li, ti, sn, mn, zr and Al, preferably Li and Zr, more preferably Li: zr=1, (0.25-3).

Inventors

  • HUANG FUQIANG
  • YE BIN
  • DONG WUJIE
  • SUN DU

Assignees

  • 中国科学院上海硅酸盐研究所

Dates

Publication Date
20260512
Application Date
20220126

Claims (11)

  1. 1. The layered structure anode material coated on the surface of the metal phosphate oligomer is characterized by comprising an anode material with a layered structure inside, wherein the surface of the anode material is a metal phosphate oligomer with a particle size of 0.5-10 nm, the structural general formula of the anode material with the layered structure is LiXO 2 , wherein X is at least one of Co, mn and Ni, the metal phosphate oligomer contains metal ions and phosphate anions, and the structural general formula of the anode material is M x (PO 4 ) y , and M is at least one of Li, ti, sn, mn, zr and Al; the preparation of the layered structure anode material coated on the surface of the metal phosphate oligomer comprises the following steps: Dissolving phosphate and a blocking agent in ethanol, uniformly mixing with a metal M salt solution to obtain a metal phosphate oligomer solution, mixing layered structure anode material powder and the metal phosphate oligomer solution, and drying and annealing the mixture to obtain the anode material with the surface coating layer-shaped structure of the metal phosphate oligomer, wherein the blocking agent is triethylamine.
  2. 2. The metal phosphate oligomer surface-coated layered structure positive electrode material according to claim 1, wherein the mass ratio of the layered structure positive electrode material to the metal phosphate oligomer is 1 (0.001-0.1).
  3. 3. The metal phosphate oligomer surface-coated layered structure positive electrode material according to claim 2, wherein the mass ratio of the layered structure positive electrode material to the metal phosphate oligomer is 1 (0.01-0.03).
  4. 4. The metal phosphate oligomer surface-coated layered structure cathode material of claim 3, wherein the mass ratio of the layered structure cathode material to the metal phosphate oligomer is 1:0.015.
  5. 5. The metal phosphate oligomer surface coated layered structure positive electrode material of any one of claims 1 to 4, wherein M is Li and Zr.
  6. 6. The metal phosphate oligomer surface-coated layered structure positive electrode material according to claim 5, wherein the molar ratio of Li: zr=1 (0.25 to 3).
  7. 7. The metal phosphate oligomer surface-coated layered structure cathode material of any one of claims 1 to 4, wherein the concentration of metal phosphate oligomer in the metal phosphate oligomer solution is 5-40 mg/mL.
  8. 8. The metal phosphate oligomer surface-coated layered structure positive electrode material of any one of claims 1 to 4, wherein the phosphate is at least one selected from phosphoric acid, monoammonium phosphate, diammonium phosphate.
  9. 9. The metal phosphate oligomer surface-coated layered structure positive electrode material according to any one of claims 1 to 4, wherein the mass ratio of the end-capping agent to the phosphate is (3 to 24) mL/1 g.
  10. 10. The metal phosphate oligomer surface coated layered structure positive electrode material of any one of claims 1 to 4, wherein the annealing temperature is 500 to 1000 ℃ for 2 to 6 hours.
  11. 11. Use of the metal phosphate oligomer surface coated layered structure positive electrode material of any one of claims 1-10 in a lithium ion battery at high voltage and low temperature, wherein the high cut-off voltage is in the range of 4.2v to 4.8v, and the low temperature is 0 to-50 ℃.

Description

Metal phosphate oligomer surface-coated layered structure positive electrode material, and preparation method and application thereof Technical Field The invention relates to preparation of a layered structure anode material coated on the surface of a metal phosphate oligomer and application of the layered structure anode material to a lithium ion battery under high voltage and low temperature, in particular to a preparation method of a metal phosphate oligomer solution, a preparation method of a metal phosphate oligomer surface coating layer structure anode material and application of the layered structure anode material to the lithium ion battery under high voltage and low temperature, and belongs to the field of lithium ion battery anode materials. Background Lithium Ion Batteries (LIBs) have been the most commonly used energy storage devices for portable electronic products, electric vehicles, power grid peak shaving and other applications because of their advantages of high volumetric energy density, mass energy density, long life, no memory effect, low self-discharge effect, environmental friendliness and the like. However, as the performance requirements of various applications on lithium ion batteries are continuously increased, the requirements on energy and power density and low-temperature environmental adaptability of the lithium ion batteries are increasingly unable to meet the actual demands. The main limiting factor is the positive electrode material, and how to improve the specific capacity, the multiplying power and the low-temperature performance of the positive electrode material is the key for realizing the breakthrough of the performance of the lithium ion battery. The improvement of the cut-off voltage can directly improve the lithium removal amount and is the most effective method for improving the specific capacity of the lithium removal device, but the improvement of the cut-off voltage also has the problems that (1) the electrode material has lattice expansion, so that the crystal structure is degraded, the performance is poor, (2) the side reaction on the surface of the electrode material is aggravated, the electrode is corroded, and (3) the oxidative decomposition of the electrolyte is aggravated. Meanwhile, the charge transfer and ion diffusion rates are positively correlated with the temperature, so that when the temperature is too low, the rapid decrease of the charge transfer and ion diffusion rates can lead to the rapid decrease of the specific capacity, the multiplying power and the cycling stability of the anode, and the application of the anode in high-altitude and high-latitude areas, especially in cold environments in winter, is greatly limited. Therefore, improving the high-voltage and low-temperature performance of the positive electrode can improve the energy density, the power density and the environmental adaptability of the lithium ion battery, and has important significance. At present, surface coating has proven to be an effective method for improving the cycling stability of the positive electrode at high voltages. For example Nie et al report the use of zinc oxide coating to improve the cycling stability of lithium cobaltate at 4.5V. As for low temperature performance, in addition to the effect of coagulation of the electrolyte at extremely low temperature (-40 ℃) the carbonate-based electrolyte has a change in ionic conductivity of less than one order of magnitude between 25 ℃ and-25 ℃, and at the same time, since the separator has a thickness of μm, the electrochemical performance thereof is hardly affected, so that the sharp increase in electrode-electrolyte interface resistance at low temperature is a major factor of deterioration of the low temperature performance thereof. The surface coating layer with high lithium ion conductivity can improve the diffusion of lithium ions at the interface and reduce interface impedance, thereby improving specific capacity, multiplying power and cycle performance at low temperature. However, the conventional coating method is relatively difficult to control and uneven in coating, so that the application potential of the conventional coating method is greatly limited. Disclosure of Invention In order to solve the problems, the invention provides a metal phosphate oligomer surface-coated layered structure anode material, a preparation method thereof and application of a lithium ion battery at high voltage and low temperature. The invention provides a layered structure anode material with a surface coated with a metal phosphate oligomer, which comprises an anode material with a layered structure inside and a metal phosphate oligomer on the surface, wherein the structural general formula of the anode material is LiXO 2, X is at least one of Co, mn and Ni, the metal phosphate oligomer contains metal ions and phosphate anions, the structural general formula of the metal phosphate oligomer is M x(PO4)y, M is at least one of Li,