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CN-121990612-A - Disordered-phase-structure lithium-rich manganese-based positive electrode material, preparation method and battery

CN121990612ACN 121990612 ACN121990612 ACN 121990612ACN-121990612-A

Abstract

The embodiment of the invention provides a disordered-phase-structure lithium-rich manganese-based positive electrode material, a preparation method and a battery, wherein a manganese source, a sodium source and a lithium source are mixed in proportion, the ratio of the mass of the sodium source to the mass of the lithium source is 1:9-9:1, the ratio of the total mass of the sodium source and the mass of the lithium source to the mass of the manganese source is 0.8-1.2:1, the mixed raw materials are placed in a porcelain boat, heating and heat preservation are carried out in a heating furnace to obtain a precursor material with a banded superstructure, the precursor material and molten salt are mixed according to the mass ratio of 1:1-20, grinding is uniform, the mixture is placed in the porcelain boat, heating and heat preservation are carried out in an air, the treated sample is washed and dried by deionized water, and the disordered-phase-structure lithium-rich manganese-based positive electrode material is obtained, so that the disordered-phase-state lithium-poor structure with disordered Li@Mn6 honeycomb distribution is obtained through the regulation and control of the precursor structure and the molten salt treatment, and the advantages of remarkably improved cycling stability and voltage retention rate of the material are maintained at low cost and high capacity are maintained.

Inventors

  • HU JIANGTAO
  • ZHANG QIANLING
  • YANG XUMING
  • DONG JINQI
  • ZHANG YUAN

Assignees

  • 深圳大学

Dates

Publication Date
20260508
Application Date
20260206

Claims (10)

  1. 1. The preparation method of the disordered-phase-structure lithium-rich manganese-based positive electrode material is characterized by comprising the following steps of: (1) Mixing a manganese source, a sodium source and a lithium source in proportion, wherein the ratio of the amount of substances of the sodium source to the amount of substances of the lithium source is 1:9-9:1, and the ratio of the total amount of substances of the sodium source and the lithium source to the amount of substances of the manganese source is 0.8-1.2:1; (2) Placing the mixed raw materials into a porcelain boat, heating to 500-700 ℃ in a heating furnace at a heating rate of 1-5 ℃ per minute, and preserving heat for 10-30 hours to obtain a precursor material with a banded super structure; (3) Mixing the precursor material and the molten salt according to the mass ratio of 1:1-20, and grinding uniformly; (4) Placing the mixture in a porcelain boat, heating to 200-400 ℃ at a heating rate of 1-5 ℃ per minute in air, oxygen or argon atmosphere, and preserving heat for 5-8 hours; (5) And washing the treated sample with deionized water and drying to obtain the lithium-rich manganese-based positive electrode material with a disordered phase structure.
  2. 2. The method of claim 1, wherein the manganese source is selected from one or more of MnCl 2 、MnCO 3 、MnNO 3 、（CH 3 COO） 2 Mn.
  3. 3. The method of claim 1, wherein the sodium source is selected from one or more of NaCl, na 2 CO 3 、NaNO 3 、CH 3 COONa.
  4. 4. The method of claim 1, wherein the lithium source is selected from one or more of LiCl, li 2 CO 3 、LiNO 3 、CH 3 COOLi.
  5. 5. The method of claim 1, wherein the molten salt is selected from one or more of the group consisting of LiNO 3 、LiCl、NaCl、NaNO 3 .
  6. 6. The method of claim 1, wherein the ratio of the amounts of the sodium source to lithium source materials is 7:3.
  7. 7. The method according to claim 1, wherein the holding time in the step (2) is 15 to 25 hours.
  8. 8. The preparation method of the glass fiber reinforced plastic composite material according to claim 1, wherein the heat preservation time in the step (4) is 6-7 hours, and the heating furnace atmosphere is oxygen.
  9. 9. The disordered-phase-structure lithium-rich manganese-based positive electrode material is characterized by being prepared by the method of any one of claims 1 to 8 and having a disordered Li@Mn 6 honeycomb-shaped distributed lithium-deficient structure.
  10. 10. A lithium ion battery comprising the disordered phase structured lithium-rich manganese-based cathode material of claim 9.

Description

Disordered-phase-structure lithium-rich manganese-based positive electrode material, preparation method and battery Technical Field The invention relates to the technical field of lithium ion battery anode materials, in particular to a disordered-phase-structure lithium-rich manganese-based anode material, a preparation method and a battery, which are suitable for a lithium ion battery system with high energy density, low cost and environmental friendliness. Background The lithium-rich manganese-based positive electrode material is regarded as one of important candidates for the positive electrode material of the next generation lithium ion battery because of the advantages of low cost, high theoretical capacity, environmental friendliness and the like. However, conventional lithium-rich manganese-based materials have serious voltage and capacity decay problems during cycling, limiting their commercial applications. At present, common improvement methods comprise transition metal doping, surface coating, structure regulation and control and the like, but the methods often introduce additional metal elements or complex processes, thereby increasing the cost and the preparation difficulty. Disclosure of Invention In view of the above, the invention provides a disordered-phase-structure lithium-rich manganese-based positive electrode material, a preparation method and a battery, and the disordered-phase-structure lithium-rich manganese-based positive electrode material is prepared by precursor structure regulation and molten salt treatment, so that a lithium-deficient structure with disordered Li@Mn 6 cellular distribution is obtained, the cycle stability and voltage retention rate of the material are remarkably improved, and meanwhile, the advantages of low cost and high specific capacity are maintained. In order to achieve the above purpose, the present invention provides the following technical solutions: in a first aspect, the invention provides a preparation method of a disordered-phase-structure lithium-rich manganese-based positive electrode material, which comprises the following steps: (1) Mixing a manganese source, a sodium source and a lithium source in proportion, wherein the ratio of the amount of substances of the sodium source to the amount of substances of the lithium source is 1:9-9:1, and the ratio of the total amount of substances of the sodium source and the lithium source to the amount of substances of the manganese source is 0.8-1.2:1; (2) Placing the mixed raw materials into a porcelain boat, heating to 500-700 ℃ in a heating furnace at a heating rate of 1-5 ℃ per minute, and preserving heat for 10-30 hours to obtain a precursor material with a banded super structure; (3) Mixing the precursor material and the molten salt according to the mass ratio of 1:1-20, and grinding uniformly; (4) Placing the mixture in a porcelain boat, heating to 200-400 ℃ at a heating rate of 1-5 ℃ per minute in air, oxygen or argon atmosphere, and preserving heat for 5-8 hours; (5) And washing the treated sample with deionized water and drying to obtain the lithium-rich manganese-based positive electrode material with a disordered phase structure. Preferably, the manganese source is selected from one or more of MnCl2, mnCO3, mnNO3, (CH 3 COO) 2 Mn. Preferably, the sodium source is selected from one or more of NaCl, na2CO3, naNO3, CH3 COONa. Preferably, the lithium source is selected from one or more of LiCl, li2CO3, liNO3, CH3 COOLi. Preferably, the molten salt is selected from one or more of LiNO3, liCl, naCl, naNO. Preferably, the ratio of the amounts of substances of the sodium source to the lithium source is 7:3. Preferably, the heat preservation time in the step (2) is 15-25 hours. Preferably, in the step (4), the heat preservation time is 6-7 hours, and the atmosphere of the heating furnace is oxygen. In a second aspect, the invention provides a disordered-phase-structure lithium-rich manganese-based positive electrode material, which is prepared by the method and has a disordered Li@Mn6 honeycomb-shaped distributed lithium-deficient structure. In a third aspect, the invention provides a lithium ion battery, comprising the above disordered phase structure lithium-rich manganese-based cathode material. Compared with the prior art, the method has the following beneficial effects: 1) The precursor with the banded super structure is prepared through the regulation and control of the proportion of sodium and lithium, the Li@Mn 6 super structure is dispersed, a disordered Li@Mn 6 distributed material is further obtained in the subsequent preparation, the disordered Li@Mn 6 distribution is realized through the structure regulation and control, and the structural stability is improved; 2) Other transition metal ions are not introduced, so that the low cost and environmental friendliness of the material are maintained; 3) The preparation process is simple and is suitable for large-scale production; 4) The material