Search

CN-121983567-A - High-entropy layered oxide and preparation method and application thereof

CN121983567ACN 121983567 ACN121983567 ACN 121983567ACN-121983567-A

Abstract

The application relates to the technical field of sodium ion batteries, and discloses a high-entropy layered oxide, a preparation method and application thereof. The high-entropy layered oxide provided by the application uses nickel-iron-manganese oxide as a basic system, a specific amount of metal elements B are used for replacing part of sodium elements in the high-entropy layered oxide, a specific amount of metal elements M, M ', M' are used for replacing part of transition metal elements (Ni, fe and Mn) and limiting the proportional relation between the metal elements M, M ', M', so that stable atomic arrangement is constructed among the elements, thereby realizing the stability of a crystal structure, being beneficial to relieving phase change, being used as an anode active material, being capable of ensuring the cycling stability of the material under high voltage or ultra-high voltage, and being capable of obviously improving the average voltage, specific discharge capacity and energy density of the sodium-electricity material. In addition, the nickel cobalt manganese oxide is used as a basic system, and the method has cost advantages compared with the copper iron manganese oxide system in the prior art.

Inventors

  • SHAO HONGYUAN
  • CHEN YUCHAO
  • KONG ZIYAN
  • LAI JING
  • Dai Tengyuan
  • ZHANG JIE

Assignees

  • 万华化学集团电池科技有限公司
  • 万华化学(烟台)电池产业有限公司
  • 万华化学(烟台)电池材料科技有限公司
  • 万华化学集团股份有限公司

Dates

Publication Date
20260505
Application Date
20241028

Claims (10)

  1. 1. A high-entropy layered oxide is characterized by having a composition formula ：Na a B b (Ni x1 M x2 M' x3 Fe y Mn z M" z' )O 2+c , shown in the specification, wherein ,0.8＜a＜1.0,0＜b＜0.2,0＜c＜0.2,0.2＜x1＜0.4,x2＞0,x3＞0,0.2＜x1+x2+x3＜0.6,0＜y＜0.4,0＜z＜0.5,0＜z'＜0.3,0.9＜x1+x2+x3+y+z+z'＜1.1, is formed by mixing (x 2 +x3) and z ' in a ratio range of 0.75-1.0, B, M, M ', M ' are metal elements, B is one of Li, K and Ca elements, M, M ' is one of Sr, cd, mg, zn, cu, ba, co elements and M ' is one of Zr, ce, W, ti elements.
  2. 2. The high-entropy layered oxide according to claim 1, wherein the high-entropy layered oxide has an α -NaFeO 2 -type layered structure, wherein the B element is doped in the Na-O octahedral layer, and the occupancy rate Occ (Na) of the Na element in the Na-O octahedral layer after the B element doping is between 75% and 95%.
  3. 3. The high entropy layered oxide of claim 1, wherein M, M ', M "are doped in the transition metal-oxygen (TM-O) octahedral layer and M, M', M" are doped with TM-O octahedral layer spacing d (O-TM-O) between Between them.
  4. 4. A method for preparing the high-entropy layered oxide according to any one of claims 1 to 3, comprising the steps of: s1, mixing a nickel-iron-manganese hydroxide precursor A containing metal elements M, M 'and M' with a sodium source and an oxide of a metal element B to obtain a mixed material; s2, sintering the mixed material in an oxygen-containing atmosphere to obtain the high-entropy layered oxide.
  5. 5. The method for preparing a high-entropy layered oxide according to claim 4, wherein in S1, the molar ratio of sodium element in the sodium source to the total amount of metal elements in the precursor a is 0.75:1 to 0.95:1; and/or, the mol ratio of the oxide of the metal element B to the total metal element in the precursor A is 0.001-0.2:1 based on the metal element B.
  6. 6. The method for preparing a high-entropy layered oxide according to claim 4, wherein in S2, the sintering temperature is 700 ℃ to 1000 ℃ and the sintering time is 3h to 20h.
  7. 7. The method for producing a high-entropy layered oxide according to any one of claims 4 to 6, wherein the sodium source comprises at least one of sodium carbonate, sodium hydroxide, sodium nitrate, and sodium acetate.
  8. 8. A positive electrode sheet, characterized by comprising: A positive electrode current collector, and The positive electrode active material layer is arranged on at least one side of the positive electrode current collector, and comprises the high-entropy layered oxide as claimed in any one of claims 1 to 3 or the high-entropy layered oxide prepared by the preparation method as claimed in any one of claims 4 to 7.
  9. 9. A sodium ion battery comprising the positive electrode sheet of claim 8.
  10. 10. An electrical device comprising the sodium ion battery of claim 9.

Description

High-entropy layered oxide and preparation method and application thereof Technical Field The application relates to the technical field of sodium ion batteries, in particular to a high-entropy layered oxide and a preparation method and application thereof. Background Sodium ion batteries have been rapidly attracting attention since ask oneself years because of their low cost of raw materials, high specific discharge capacity, long cycle life, low self-discharge rate, good environmental friendliness, and the like. However, with the rapid development of new energy industries, power and energy storage batteries have raised higher requirements on energy density, safety and cycle life, and conventional sodium ion batteries have also faced great challenges. Currently, sodium ion batteries are in a research stage, and commercial sodium ion battery cathode materials are not available. Sodium-electric layered oxide Na xMO2 (wherein M represents a 3d transition metal element, which may contain one or more elements such as Ti, V, cr, fe, mn, co, ni, cu, nb, ru, mo, zn, etc.) has attracted extensive attention from researchers because of its abundant compositional diversity and controllable electrochemical properties, and research on sodium-ion batteries is now focused mainly on oxide cathode materials of layered structure. However, the sodium-electricity layered oxide material has the defects of low voltage platform, low discharge capacity, short cycle life under high voltage or ultra-high voltage, poor safety and the like. How to greatly improve the discharge voltage platform of the sodium-electricity layered oxide material so as to achieve the aim of improving the energy density, and simultaneously ensure the cycling stability of the material under high voltage or ultra-high voltage to become the problem of industry pain points. Disclosure of Invention The application provides a high-entropy layered oxide and a preparation method and application thereof, and aims to solve the problems of low voltage platform, low discharge capacity, short cycle life under high voltage or ultra-high voltage, poor safety and the like of a sodium-electricity layered oxide material in the prior art. In a first aspect, the application provides a high-entropy layered oxide, which has a composition formula ：NaaBb(Nix1Mx2M'x3FeyMnzM"z')O2+c, shown in the specification, wherein ,0.8＜a＜1.0,0＜b＜0.2,0＜c＜0.2,0.2＜x1＜0.4,x2＞0,x3＞0,0.2＜x1+x2+x3＜0.6,0＜y＜0.4,0＜z＜0.5,0＜z'＜0.3,0.9＜x1+x2+x3+y+z+z'＜1.1, is formed by mixing (x 2 +x3) and z ' in a ratio range of 0.75-1.0, B, M, M ', M ' are metal elements, B is one of Li, K and Ca elements, M, M ' is one of Sr, cd, mg, zn, cu, ba, co elements and M ' is one of Zr, ce, W, ti elements. In some alternative embodiments, the high-entropy layered oxide has an α -NaFeO 2 type layered structure, wherein the B element is doped in the Na-O octahedral layer, and the occupancy rate Occ (Na) of the Na element in the Na-O octahedral layer after the B element doping is between 75% and 95%. In some alternative embodiments, M, M ', M "elements are doped in the transition metal-oxygen (TM-O) octahedral layer, and M, M', M" elements are doped with a TM-O octahedral layer spacing d (O-TM-O) betweenBetween them. In a second aspect, the present application provides a method for preparing the above high entropy layered oxide, comprising the steps of: s1, mixing a nickel-iron-manganese hydroxide precursor A containing metal elements M, M 'and M' with a sodium source and an oxide of a metal element B to obtain a mixed material; s2, sintering the mixed material in an oxygen-containing atmosphere to obtain the high-entropy layered oxide. In some optional embodiments, in S1, the molar ratio of the sodium element in the sodium source to the total amount of metal elements in the precursor a is 0.75:1 to 0.95:1; and/or, the mol ratio of the oxide of the metal element B to the total metal element in the precursor A is 0.001-0.2:1 based on the metal element B. In some alternative embodiments, in S2, the sintering temperature is 700 ℃ to 1000 ℃ and the sintering time is 3 hours to 20 hours. In some alternative embodiments, the sodium source comprises at least one of sodium carbonate, sodium hydroxide, sodium nitrate, sodium acetate. In a third aspect, the present application provides a positive electrode sheet comprising: A positive electrode current collector, and The positive electrode active material layer is arranged on at least one side of the positive electrode current collector and comprises the high-entropy layered oxide or the high-entropy layered oxide prepared by the preparation method. In a fourth aspect, the present application provides a sodium ion battery, comprising the positive electrode sheet described above. In a fifth aspect, the present application provides an electrical device comprising a sodium ion battery as described above. The technical scheme of the application has the following advantages: The high-entropy laye