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CN-122025593-A - Core-shell spherical-structure sodium nickel manganese oxide positive electrode material and preparation method and application thereof

CN122025593ACN 122025593 ACN122025593 ACN 122025593ACN-122025593-A

Abstract

The invention discloses a nickel sodium manganate positive electrode material with a core-shell spherical structure, a preparation method and application thereof, wherein the material has a P2 type layered structure, a morphology of the material is a core-shell structure, and a chemical general formula of the material is as follows . When Ni is doped into the P2 layered oxide, a strong Ni-O bond is formed with an O atom to promote the bonding energy, and then an Mn-O-Ni covalent bond is formed by sharing the O atom with an Mn atom, so that the stability of a crystal structure is enhanced, and the lattice expansion is slowed down. The core-shell spherical structure of the positive electrode material has rough surface and multiple cavities inside, can wrap the inner layer material, reduce direct contact with electrolyte and prevent Dissolving, reducing side reaction, reducing inner core volume expansion during charge and discharge, inhibiting phase change, and improving structural stability. In addition, the structure is optimized, the electron conduction path is shortened, the internal resistance is reduced, the multiplying power performance and the circulation stability are improved, and the method has important application value in the fields of sodium ion battery electrode preparation and energy storage equipment research.

Inventors

  • WANG ZHITAO
  • Ji Manyu
  • ZHAO DENGKE
  • WANG LIYUAN
  • Li Linpo
  • LI JIAJIA
  • ZHAI HAIFA
  • WANG LI
  • SHANGGUAN ENBO

Assignees

  • 河南师范大学

Dates

Publication Date
20260512
Application Date
20260225

Claims (10)

  1. 1. A sodium nickel manganese oxide positive electrode material with a core-shell spherical structure is characterized in that the positive electrode material is in a single crystal form and has a P2 type layered structure, and the chemical general formula is Wherein y is more than or equal to 0 and less than or equal to 0.6.
  2. 2. The core-shell spherical structure sodium nickel manganese oxide positive electrode material according to claim 1, wherein the positive electrode material has a stable network structure composed of Ni-O bonds and Mn-O-Ni covalent bonds.
  3. 3. A method for preparing the core-shell spherical structure sodium nickel manganese oxide positive electrode material according to any one of claims 1 or 2, which is characterized by comprising the following steps of S1 adopting a coprecipitation method Precursor S2 to be prepared Fully mixing the precursor powder with an excessive sodium source, and finally preparing the core-shell spherical structure sodium nickel manganese oxide anode material by adopting a high-temperature solid phase method 。
  4. 4. The method for preparing a core-shell spherical structure sodium nickel manganese oxide positive electrode material according to claim 3, wherein in the step S1, the manganese source used in the coprecipitation method is 、 、 Or (b) The nickel source is 、 、 Or (b) 。
  5. 5. The method for preparing the core-shell spherical structure sodium nickel manganese oxide positive electrode material according to claim 4, wherein in the step S2, a high-temperature solid phase method is adopted, the mixed materials are placed in a muffle furnace, and sintering treatment is carried out for 4-15 hours at a high temperature of 700-900 ℃ to finally prepare the core-shell spherical structure sodium nickel manganese oxide positive electrode material 。
  6. 6. The method for preparing a core-shell spherical structure sodium nickel manganese oxide positive electrode material according to claim 5, wherein the sodium source in the step S2 is 、 、 Or (b) The reaction atmosphere is air atmosphere, and the heating rate of high-temperature sintering is 3-10 ℃ per minute.
  7. 7. The method for preparing a core-shell spherical structure sodium nickel manganese oxide positive electrode material according to claim 6, wherein the method comprises the following steps of The precursor is prepared through the steps of mixing And Preparing 150-250 mL of mixed solution A, adding 50-150 mL of absolute ethyl alcohol, and preparing 30-mmol of solution B Dissolving in 150-250 mL deionized water, placing the solution A in a constant-temperature water bath kettle to keep a constant-temperature water bath at 50 ℃, adding the prepared solution B into the solution A, aging after the completion of the solution A, keeping the temperature for 0.5-1.5 h, keeping constant speed stirring and constant temperature in the process, and finally centrifugally washing the precipitate obtained by the reaction, and drying at 80 ℃ to obtain a spherical shape And the precursor is in a earthy yellow powder shape.
  8. 8. The preparation method of the core-shell spherical sodium nickel manganese oxide positive electrode material according to claim 7, wherein the positive electrode material comprises the following specific preparation steps of adding 5% of 7.35mmol NaOH and 10mmol Sequentially adding absolute ethyl alcohol into an agate mortar, fully grinding into slurry under a baking lamp, baking, taking out, grinding into powder, placing into a porcelain boat, placing into a muffle furnace, heating to 750-850 ℃ at a heating rate of 3-6 ℃ per minute, and preserving heat for 6-15 h to finally obtain black And a positive electrode material.
  9. 9. A sodium ion battery comprising the core-shell spherical sodium nickel manganese oxide positive electrode material according to any one of claims 1 or 2.
  10. 10. Use of the core-shell spherical structure sodium nickel manganese oxide positive electrode material according to any one of claims 1 or 2 in sodium ion batteries.

Description

Core-shell spherical-structure sodium nickel manganese oxide positive electrode material and preparation method and application thereof Technical Field The invention belongs to the technical field of manganese-based sodium electric materials, and particularly relates to a core-shell spherical structure sodium nickel manganese oxide positive electrode material, and a preparation method and application thereof. Background Under the background of global energy structure transformation, the limited reserves and the gradual deterioration of the ecological environment of traditional fossil fuels promote the development of new energy technologies to become key factors related to human sustainable development. As an important research direction in the energy storage field, sodium ion battery technology is gradually becoming a powerful alternative to lithium ion batteries due to its resource advantages and cost effectiveness. Especially in the aspect of research of anode materials, the innovative discovery of the manganese-based layered oxide opens up a new way for developing high-performance and economic sodium ion batteries. Among them, the P2 type layered oxide has become one of the most potential positive electrode materials in this field due to its unique crystal structure and excellent electrochemical properties, and has been paid attention to in academia and industry. The material has double advantages in energy density and cost control, and provides important technical support for promoting the industrialized development of sodium ion batteries. The P2 type layered metal oxide has the advantages of being spaciousIon transmission channels, easy synthesis, high specific capacity and the like occupy important roles in the research of sodium ion battery anode materials, and particularly a manganese-based system is paid attention to because of excellent comprehensive performance. However, such materials still present challenges in practical applications, such as the ease of Jahn-Teller effect, andThe oxidation-reduction pair has a relatively low reaction potential, suppresses the increase of energy density, and is susceptible to phase transition at an operating voltage higher than 4.0V, resulting in deterioration of cycle stability. Researchers are working on improving these problems through various material modification means, mainly including strategies of regulating crystal structure by element doping, optimizing electronic properties by ion substitution, improving interface stability by surface coating, and the like. The development and application of the technical approaches have important practical application values for improving the structural stability of the P2 type layered oxide under the high-voltage condition, and are important research directions in the current sodium ion battery field. Patent literature of CN 202410583789.1 discloses a double-position doped sodium nickel iron manganese oxide positive electrode material, a preparation method and application thereof, and the double-position doped sodium nickel iron manganese oxide positive electrode material has the following structural general formula: The preparation method comprises the steps of dissolving nickel salt, ferric salt and manganese salt in an alcohol-containing solvent, adding ascorbic acid M salt to obtain a mixed solution, adding a complexing agent and a precipitating agent into the mixed solution, performing coprecipitation reaction under an inert gas atmosphere to obtain an M-doped nickel-iron-manganese hydroxide precursor, uniformly mixing sodium salt and potassium salt, adding the sodium salt and the potassium salt into the M-doped nickel-iron-manganese hydroxide precursor, uniformly mixing, sintering under an oxidizing gas atmosphere, and cooling under the inert gas atmosphere to obtain the double-position doped nickel-iron-manganese sodium oxide anode material. Under the double-position doping effect, the specific capacity, the first efficiency and the capacity cycling stability of the positive electrode material can be improved. Aiming at the defects, the current research mainly focuses on the following improvement strategies of (1) element doping, namely stabilizing a layered structure and inhibiting phase change by introducing Ni, W, ti, zn, la and other elements, (2) surface modification, namely adopting carbon coating or perovskite modification, reducing side reaction of electrolyte and active substances, improving interface stability, and (3) anion redox regulation, namely activating oxygen anions to participate in charge compensation, replacing partial transition metal redox reaction and relieving structural stress. These improved strategies have significantly improved P2-The cycle service life and the multiplying power performance of the product lay a foundation for the commercial application of the product. The above-described improvement strategy is still to be further improved and optimized. Disclosure of Invention