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CN-118352526-B - Application of lithium nitrilotriacetate as coating additive for positive electrode material and application of lithium nitrilotriacetate in positive electrode material

CN118352526BCN 118352526 BCN118352526 BCN 118352526BCN-118352526-B

Abstract

The invention discloses application of lithium nitrilotriacetate as a coating additive for a positive electrode material and application of the lithium nitrilotriacetate in the positive electrode material, wherein the lithium nitrilotriacetate is adopted as the coating additive for the positive electrode material, on one hand, the nitrilotriacetate ions can be complexed with metal ions on the surface of the positive electrode material, so that the formation of a subsequent lithium ion guiding layer is facilitated, meanwhile, the stability of coating of a coating layer can be improved, and the falling of the coating layer is inhibited; on the other hand, the lithium salt can prevent the direct use of nitrilotriacetic acid from corroding the anode material and damaging the material structure, can also be used as a lithium supplementing agent for providing lithium ions for the anode material, and simultaneously avoids introducing other metal ions and eliminates the adverse effect of other metal ions on the index performance of the anode material.

Inventors

  • HUANG LONGSHENG
  • RUAN DINGSHAN
  • LIU WEIJIAN
  • YUAN LING
  • Qu Weicong
  • LI CHANGDONG

Assignees

  • 广东邦普循环科技有限公司
  • 湖南邦普循环科技有限公司

Dates

Publication Date
20260505
Application Date
20240415

Claims (11)

  1. 1. A method for preparing a positive electrode material, comprising: Mixing matrix particles with a water washing liquid containing lithium nitrilotriacetate, washing with water, and then carrying out solid-liquid separation and secondary drying to obtain the positive electrode material, wherein the molecular formula of the lithium nitrilotriacetate is C 6 H 9-x NO 6 Li x , and x=1, 2 or 3; The preparation method of the lithium nitrilotriacetate comprises the steps of reacting lithium hydroxide with nitrilotriacetic acid in a solution system, and drying a product for the first time after the reaction is finished to obtain the lithium nitrilotriacetate; The positive electrode material comprises a matrix and a coating layer coated on the matrix, wherein the matrix is a ternary material, the coating layer comprises lithium ions and nitrilotriacetic acid radical, and the mass fraction of the nitrilotriacetic acid radical in the positive electrode material is 0.1% -1.5%.
  2. 2. The method for producing a positive electrode material according to claim 1, wherein a molar ratio of lithium hydroxide to nitrilotriacetic acid is 1 to 3.
  3. 3. The method for preparing a positive electrode material according to claim 1, wherein the reaction time is 10min to 120min and the pH of the solution is 6 to 8.
  4. 4. The method for producing a positive electrode material according to claim 1, wherein the first drying temperature is 80 ℃ to 150 ℃ for 12 hours to 48 hours.
  5. 5. The method of claim 1, wherein the matrix chemical formula is LiNi a Co b Mn c O 2 , wherein a+b+c=1, wherein 0.8 < a <1,0< b < 0.2,0< c < 0.2.
  6. 6. The method for producing a positive electrode material according to claim 2, wherein the concentration of lithium nitrilotriacetate in the aqueous solution is 5g/L to 100g/L; and/or the mass ratio of the matrix to the washing liquid is 0.4-2.
  7. 7. The method for producing a positive electrode material according to claim 6, wherein the mass ratio of the base to the aqueous washing solution is 0.5 to 1.
  8. 8. The method for producing a positive electrode material according to claim 1, wherein the time of the water washing step is 0.5min to 3min; And/or, the water washing step is accompanied by stirring, and the stirring speed is 80rpm-300rpm; and/or the pressure of the second drying step is 10 2 Pa~10 5 Pa; And/or the temperature of the second drying step is 90-150 ℃ and the time is 5-24 h.
  9. 9. A positive electrode sheet comprising the positive electrode material produced by the production method according to any one of claims 1 to 8.
  10. 10. A lithium ion battery comprising the positive electrode sheet of claim 9.
  11. 11. An electrical device comprising the lithium-ion battery of claim 10.

Description

Application of lithium nitrilotriacetate as coating additive for positive electrode material and application of lithium nitrilotriacetate in positive electrode material Technical Field The invention relates to the technical field of lithium battery anode materials, in particular to application of lithium nitrilotriacetate as a coating additive for an anode material and application of the lithium nitrilotriacetate in the anode material. Background The next generation battery with lower development cost, longer cycle life and better performance is of great importance for the deployment of lithium ion batteries in electric vehicles and power grid systems. The positive electrode material is used as a main component of the lithium ion battery, and the performance of the positive electrode material plays a key role in the overall performance of the lithium ion battery. Recently, in order to further increase the energy density of the current lithium ion battery, high-nickel ternary layered oxides and high-voltage ternary layered oxides have become research hot spots in the battery world. However, the increasing nickel content and application voltage in the current layered cathode brings a series of tests, and the high nickel content and high application voltage make the problems of chemical mechanical stability, thermal stability, structural stability, interface stability and the like of materials more prominent, so that the commercial deployment of the materials is very challenging. The coating can change the inherent surface interface property of the material, and is an effective means for improving the interface stability of the ternary positive electrode material and improving the electrochemical performance of the ternary positive electrode material. However, the type of the coating agent and the coating method have great influence on the electrical properties of the coating modified ternary positive electrode material, so that the selection of a proper coating agent and a proper coating method is important. Disclosure of Invention The invention aims to provide application of lithium nitrilotriacetate as a coating additive for a positive electrode material and application of the lithium nitrilotriacetate in the positive electrode material, and improve the cycle performance of the positive electrode material. The invention is realized in the following way: In a first aspect, the present invention provides the use of lithium nitrilotriacetate having the formula C 6H9-xNO6Lix, wherein x=1, 2 or 3, as a coating additive for positive electrode materials. In a second aspect, the present invention provides a method for preparing a coating additive for a positive electrode material according to the foregoing embodiment, including: reacting lithium hydroxide and nitrilotriacetic acid in a solution system to obtain the coating additive for the positive electrode material; Preferably, the molar ratio of lithium hydroxide to nitrilotriacetic acid is between 1 and 3; Preferably, the reaction time is 10min-120min, and the pH value of the solution is 6-8; preferably, after the reaction is completed, the product is dried for a first time, the first drying temperature is 80-150 ℃ and the time is 12-48 hours. In a third aspect, the invention provides a positive electrode material, which comprises a matrix and a coating layer coated on the matrix, wherein the matrix is a ternary material, the coating layer comprises lithium ions and nitrilotriacetic acid, and the mass fraction of the nitrilotriacetic acid in the positive electrode material is 0.1% -1.5%. In a fourth aspect, the present invention provides a method for preparing a positive electrode material according to the foregoing embodiment, including: Mixing the matrix particles with a water washing liquid containing lithium nitrilotriacetate, washing with water, and then carrying out solid-liquid separation and secondary drying to obtain the positive electrode material. In some embodiments, the matrix chemical formula is LiNi aCobMncO2, where a+b+c=1, where 0.8+.a <1,0< b+.0.2, 0< c+.0.2. In some embodiments, the concentration of lithium nitrilotriacetate in the aqueous wash solution is from 5g/L to 100g/L; and/or the mass ratio of the matrix to the aqueous wash solution is 0.4-2, preferably 0.5-1. In some embodiments, the time of the washing step is 0.5min-3min; And/or, the water washing step is accompanied by stirring, and the stirring speed is 80rpm-300rpm; and/or the pressure of the second drying step is 10 2Pa ~105 Pa; And/or the temperature of the second drying step is 90-150 ℃ and the time is 5-24 h. In a fifth aspect, the present invention provides a positive electrode sheet comprising a positive electrode material as described in the foregoing embodiments or a positive electrode material prepared by a preparation method as described in any one of the foregoing embodiments. In a sixth aspect, the present invention provides a lithium ion battery, including the posit