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CN-121990613-A - Preparation method of layered oxide positive electrode material of sodium ion battery

CN121990613ACN 121990613 ACN121990613 ACN 121990613ACN-121990613-A

Abstract

The invention provides a preparation method of a layered oxide cathode material of a sodium ion battery, which comprises the following steps of accurately weighing a binary precursor Na a Fe x Mn 1‑y O 2 of iron and manganese and a sodium source compound according to the molar ratio of elements in a chemical general formula, adding a fluxing agent and a lattice doping agent, fully mixing in a dry mixing mode to obtain a dispersion mixture, carrying out primary sintering on the dispersion mixture obtained in the step S1 in an oxygen-enriched atmosphere, cooling, crushing and classifying screening to obtain sintered powder, fully mixing the sintered powder obtained in the step S2 with a coating agent, carrying out secondary sintering in the oxygen-enriched atmosphere, and carrying out cooling, crushing and classifying screening to obtain the layered oxide cathode material of the sodium ion battery. The components of the invention are dispersed uniformly, the element allocation is precise, the prepared positive electrode material has excellent performance, and meanwhile, the whole process flow does not need to use organic solvents or produce harmful wastewater, thereby completely meeting the requirements of green and environment protection.

Inventors

  • WANG WANXIN
  • HUANG WANMING
  • ZHANG QIJUN
  • Wan Disheng
  • LU QIANG
  • YANG HONGJIN
  • HUANG ZILIANG

Assignees

  • 湖北双环科技股份有限公司

Dates

Publication Date
20260508
Application Date
20251231

Claims (10)

  1. 1. A preparation method of a layered oxide positive electrode material of a sodium ion battery is characterized in that the main component of the positive electrode material has a chemical formula of Na a Fe x Mn 1-y O 2 , wherein a is more than or equal to 0.30 and less than or equal to 0.80,0.2, x is more than or equal to 0.8, and y is more than or equal to 0.2 and less than or equal to 0.8; the method comprises the following steps: S1, accurately weighing Fe x Mn 1-y （OH） 2 which is a binary precursor of iron and manganese and a sodium source compound according to the molar ratio of each element in a chemical general formula, adding a fluxing agent and a lattice doping agent, and fully mixing in a dry mixing mode to obtain a dispersion mixture; S2, sintering the dispersion mixture obtained in the step S1 for the first time in an oxygen-enriched atmosphere at the sintering temperature of 880-980 ℃ for 8-15 hours, and then cooling, crushing and classifying and sieving to obtain sintered powder; And S3, fully mixing the sintering powder obtained in the step S2 with a coating agent, performing secondary sintering under an oxygen-enriched atmosphere, wherein the sintering temperature is 500-750 ℃, the heat preservation time is 4-8 hours, and then cooling, crushing and classifying sieving to obtain the layered oxide cathode material of the sodium ion battery.
  2. 2. The method for preparing a layered oxide cathode material for sodium-ion batteries according to claim 1, wherein in the step S1, the ratio of the total molar amount of sodium element to the total molar amount of transition metal element is 1:0.3-1.0.
  3. 3. The method for preparing a layered oxide cathode material for sodium ion batteries according to claim 1, wherein in the step S1, the sodium source is one or more selected from sodium carbonate, sodium hydroxide and sodium nitrate.
  4. 4. The method for preparing a layered oxide cathode material for a sodium ion battery according to claim 1, wherein in the step S1, the fluxing agent is selected from one or more of boric acid, boron oxide, ammonium molybdate, monoammonium phosphate, diammonium phosphate, barium oxide, calcium oxide, and tungsten oxide, and the total mass of the fluxing agent accounts for 0.01% -1% of the total mass of the precursor and the sodium source.
  5. 5. The method for preparing a layered oxide cathode material for a sodium ion battery according to claim 1, wherein in the step S1, the lattice dopant is selected from one or more of oxides, carbonates and hydroxides of magnesium, aluminum, titanium, zinc, copper, aluminum and lithium, and the total mass of the lattice dopant is 0.1% -7.0% of the total mass of the precursor and the sodium source.
  6. 6. The method for preparing a layered oxide cathode material for a sodium ion battery according to claim 1, wherein in the step S2, the powder size of the classified sieving is 400 mesh or less.
  7. 7. The method for preparing a layered oxide cathode material for a sodium ion battery according to claim 1, wherein in the step S3, the coating agent is one or more selected from the group consisting of alumina, aluminum phosphate, titanium oxide and zirconium oxide, and the total mass of the coating agent element is 0.1% -1.5% of the total mass of the sintered powder obtained in the step S2.
  8. 8. The method for preparing a layered oxide cathode material for sodium ion batteries according to claim 1, wherein in the step S3, the median particle diameter D50 of the layered oxide cathode material for sodium ion batteries is controlled to be 3.0-8.0 μm by classification and sieving.
  9. 9. The method for preparing a layered oxide cathode material for a sodium ion battery according to claim 1, wherein in the steps S2 and S3, the oxygen-enriched atmosphere is pure oxygen or an oxygen-nitrogen mixed gas with an oxygen volume concentration of not less than 20%.
  10. 10. A method for preparing a layered oxide cathode material of a sodium ion battery according to any one of claims 1 to 9.

Description

Preparation method of layered oxide positive electrode material of sodium ion battery Technical Field The application belongs to the technical field of electrochemistry, and particularly relates to a preparation method of a layered oxide positive electrode material of a sodium ion battery. Background With the acceleration of global energy structure transformation, there is an increasing need for large-scale, low-cost energy storage systems. The sodium ion battery has the remarkable advantages of wide sources of raw materials and low cost, and becomes one of ideal energy storage technologies for supporting renewable energy grid connection and intelligent power grid development. Among the numerous sodium-electricity positive electrode materials, iron-manganese-based layered transition metal oxide (Na aFexMn1-yO2) is considered as one of the positive electrode material systems with the largest commercial application prospect due to its combination of low cost of iron element, environmental friendliness and high operating voltage and high capacity characteristics of manganese element. However, this material system still faces significant challenges in the actual industrial manufacturing process. The solid phase method synthesis process commonly adopted at present has inherent limitations that sodium source, iron source, manganese source oxide or carbonate and other powders are directly sintered at high temperature after being mixed by a mechanical dry method. Firstly, because the iron and manganese raw materials are difficult to realize uniform dispersion on an atomic scale, local components in the final product deviate from stoichiometric ratio, and a hetero-phase is easy to generate. The non-uniformity can cause inconsistent phase change behavior in the charge-discharge process, and seriously impair the cycle stability and batch consistency of the materials. Secondly, manganese element is easy to generate disproportionation reaction during high-temperature sintering, so that active material loss and interface structure degradation can be caused, and capacity fading is accelerated. The traditional dry mixing process may aggravate local manganese enrichment due to insufficient contact, and accelerate this side reaction. In addition, the process is extremely sensitive to the sintering regime. When the precursor with uneven mixing is sintered, the reaction degree between the sodium source and the transition metal oxide is different, so that excessive or insufficient partial sodium volatilization is easily caused, the out-of-control degree and irreversible phase change of sodium vacancy order are caused, the initial capacity of the material is reduced, and the structural stability of the material is influenced. Meanwhile, dust generated in the process also forms a potential threat to the production environment and the health of operators. Therefore, the development of a preparation method capable of realizing uniform mixing of molecular grades, accurately controlling the stoichiometric ratio and effectively inhibiting manganese dissolution and harmful phase change is important for breaking through the performance bottleneck of the ferro-manganese-based layered oxide cathode material. The method also has the characteristics of simple and convenient process, environmental protection, easy amplification and the like, so as to meet the urgent requirements of the future large-scale energy storage market on the high-performance and low-cost sodium ion battery. Disclosure of Invention In order to solve at least one technical problem, a preparation process which is relatively simple in process, relatively uniform in component dispersion, relatively precise in element allocation and relatively excellent in performance of the prepared positive electrode material is developed. On the one hand, the application provides a preparation method of a layered oxide positive electrode material of a sodium ion battery, wherein the main component of the positive electrode material has a chemical formula of Na aFexMn1-yO2, a is more than or equal to 0.30 and less than or equal to 0.80,0.2, x is more than or equal to 0.8, and y is more than or equal to 0.2 and less than or equal to 0.8; the method comprises the following steps: S1, accurately weighing Fe xMn1-y（OH）2 which is a binary precursor of iron and manganese and a sodium source compound according to the molar ratio of each element in a chemical general formula, adding a fluxing agent and a lattice doping agent, and fully mixing in a dry mixing mode to obtain a dispersion mixture; S2, sintering the dispersion mixture obtained in the step S1 for the first time in an oxygen-enriched atmosphere at the sintering temperature of 880-980 ℃ for 8-15 hours, and then cooling, crushing and classifying and sieving to obtain sintered powder; And S3, fully mixing the sintering powder obtained in the step S2 with a coating agent, performing secondary sintering under an oxygen-enriched atmosphere,