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CN-117185355-B - Method for preparing P2 type high-temperature phase layered oxide positive electrode material by low-temperature calcination

CN117185355BCN 117185355 BCN117185355 BCN 117185355BCN-117185355-B

Abstract

The invention relates to a method for preparing a P2 type high-temperature phase layered oxide positive electrode material by low-temperature calcination. The molecular formula of the P2 type high temperature phase layered oxide positive electrode material is Na x Li y TM 1‑y O 2 , wherein TM is at least one transition metal element, preferably Mn, ni, fe, mg, ca, al, co, x is more than or equal to 0.6 and less than or equal to 0.8, y is more than or equal to 0 and less than or equal to 0.3, the method comprises the steps of (1) weighing a sodium source, a lithium source and a transition metal source according to the molecular formula Na x TMO 2 of the P2 type high temperature phase layered oxide positive electrode material, mixing, pressing to obtain a prefabricated body, (2) calcining the obtained prefabricated body to obtain the P2 type high temperature phase layered oxide positive electrode material, wherein the calcining comprises high temperature calcining and then low temperature calcining, or the calcining comprises first low temperature calcining, high temperature calcining and finally second low temperature calcining.

Inventors

  • WEN ZHAOYIN
  • CHEN YOUMEI
  • WU XIANGWEI
  • JIN JUN

Assignees

  • 中国科学院上海硅酸盐研究所

Dates

Publication Date
20260512
Application Date
20230822

Claims (6)

  1. 1. A method for preparing a P2 type high temperature phase layered oxide positive electrode material for a sodium ion battery by auxiliary low temperature calcination is characterized by comprising the steps of preparing a P2 type high temperature phase layered oxide positive electrode material for a sodium ion battery with a chemical formula of Na x Li y TM 1-y O 2 , wherein TM is a transition metal element Mn, x is more than or equal to 0.6 and less than or equal to 0.8, y is more than or equal to 0 and less than or equal to 0.3, weighing a sodium source, a lithium source and a transition metal source according to the chemical formula of Na x Li y TM 1-y O 2 of the P2 type high temperature phase layered oxide positive electrode material, uniformly mixing, pressing and forming to obtain a prefabricated body, calcining the obtained prefabricated body under the atmosphere of air at normal pressure to obtain the P2 type high temperature phase layered oxide positive electrode material, and preserving heat at 950 ℃ for 30min and then at 750 ℃ for 12 h.
  2. 2. The method of claim 1, wherein the sodium source is selected from at least one of sodium carbonate, sodium oxide, and sodium hydroxide, the lithium source is selected from at least one of lithium carbonate, lithium oxide, and lithium hydroxide, and the transition metal source is selected from at least one of carbonate, oxide, and hydroxide of transition metal Mn.
  3. 3. The method of claim 1, wherein the mixing mode is grinding, the grinding rotating speed is 100-1500 rpm, the grinding time is 15 min-6 h, the used solvent is deionized water, absolute ethyl alcohol or isopropanol, the grinding comprises manual grinding, ball milling or sanding, the ball milling parameters comprise 200-300 rpm, the time is 2-4 h, the used solvent is deionized water, absolute ethyl alcohol or isopropanol, the sanding parameters comprise 500-1000 rpm, the time is 30 min-2 h, and the used solvent is deionized water, absolute ethyl alcohol or isopropanol.
  4. 4. The method of claim 1, wherein the amount of the sodium source is 1 wt% -15 wt% in excess of the stoichiometric ratio, and the amount of the lithium source is 1 wt% -15 wt% in excess of the stoichiometric ratio.
  5. 5. The method of claim 1, wherein the rate of temperature rise and the rate of temperature reduction of the calcination are each 1-5 ℃ per minute.
  6. 6. The method according to claim 1, wherein the P2 type high temperature phase layered oxide positive electrode material is an oxide solid powder, and the primary particle size thereof is 0.1-10 μm.

Description

Method for preparing P2 type high-temperature phase layered oxide positive electrode material by low-temperature calcination Technical Field The invention relates to a method for preparing a P2 type high Wen Xiangna ion layered positive electrode material by low-temperature calcination and a sodium ion battery containing the positive electrode, belonging to the fields of energy materials and energy storage. Background Low cost, high performance sodium ion batteries are an important technological route for large scale energy storage. The positive electrode is one of the key components for determining the energy density of sodium ion batteries, and layered oxides are of great interest due to the variety of components and high specific capacity. The solid phase method is simple to operate, can realize industrialized mass production, and is one of the most common methods for synthesizing the layered oxide. The sodium ion layered oxide positive electrode material is researched to be in a P3 type and an O3 type, and the two types have advantages. Compared with the O3 type layered oxide positive electrode material, the P2 type high Wen Xiangzheng electrode material has simpler structural phase change and better cycle stability, but the high temperature (> 900 ℃) and long-time (> 12 h) calcining mode in the conventional solid-phase calcining process not only increases the production cost, but also aggravates the phenomena of fusion aggregation and pulverization of particles, and is not beneficial to the rapid deintercalation and electrochemical cycle stability of sodium ions. Therefore, how to optimize the size and morphology of the particles, improve the rate capability and prolong the cycle life is a problem to be solved in the commercialization process of the P2 high-temperature phase layered cathode material. In order to solve the problem of particle fusion agglomeration in the process of preparing the P2 type high temperature phase layered oxide cathode material by the traditional solid phase synthesis method, a series of measures are adopted, wherein Chinese patent CN116093307B is subjected to preliminary precipitation by Mn xNiy(OH)2 to realize atomic-level mixing, and is combined with twice calcination to prepare the uniform flaky monocrystal P2 type high temperature phase layered cathode material, chinese patent 1 (publication No. CN 116177606) discloses a method for rapidly synthesizing the P2' -Na 0.67MnO2 cathode material, and small monocrystal particles with hundreds of nanometers are prepared by twice calcination (the energizing current is 47-49A and the duration is 30-60 s). Although the method can effectively optimize the size and shape of the anode particles and improve the electrochemical performance, the method involves complex process flow, increases the production cost and is difficult to realize mass production. Therefore, the solid-phase method for preparing the P2 type positive electrode material is easy to operate, low in cost and high in efficiency, the calcining temperature is reduced, the calcining time is shortened, the size and shape of the positive electrode particles are improved, the electrochemical performance is optimized, and the method has high practical value for large-scale development and application of the high-energy-density sodium ion positive electrode material on the premise of ensuring the high crystallinity of the material. Disclosure of Invention The invention provides a method for preparing a P2 type high Wen Xiangna ion layered positive electrode material by low-temperature calcination and a sodium ion battery comprising the positive electrode, and aims to solve the problems of high production cost (calcination temperature-900 ℃, heat preservation time-20 h), serious particle fusion and agglomeration, poor size and shape uniformity and the like in the conventional solid-phase method for preparing the P2 type high-temperature layered oxide positive electrode material. In one aspect, the invention provides a method for preparing a P2 type high temperature phase layered oxide positive electrode material by low temperature calcination, wherein the molecular formula of the P2 type high temperature phase layered oxide positive electrode material is Na xLiyTM1-yO2, wherein TM is at least one transition metal element, preferably Mn, ni, fe, mg, ca, al, co, x is more than or equal to 0.6 and less than or equal to 0.8, and y is more than or equal to 0 and less than or equal to 0.3; The method comprises the following steps: (1) Weighing a sodium source, a lithium source and a transition metal source according to the molecular formula Na xTMO2 of the P2 type high-temperature phase layered oxide anode material, mixing, and pressing to obtain a preform; (2) Calcining the obtained preform to obtain the P2 type high-temperature phase layered oxide anode material; the calcining comprises high-temperature calcining and then low-temperature calcining; Or the calcining comprises the st