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CN-122000320-A - Modified layered transition metal oxide material and preparation method and application thereof

CN122000320ACN 122000320 ACN122000320 ACN 122000320ACN-122000320-A

Abstract

The invention relates to the technical field of sodium ion batteries, in particular to a modified layered transition metal oxide material, a preparation method and application thereof. The modified layered transition metal oxide material comprises a doped modified layered transition metal oxide inner core and a coating layer coated on the surface of the inner core, wherein the doped modified layered transition metal oxide inner core is Na x Ni a Mn b M c O 2 , 0.5< x <1,0< a <0.33,0< b <0.67, a+b+c= 1;M is selected from at least three of Ti 4+ 、Zn 2+ 、Mg 2+ 、Cu 2+ 、W 5+ 、Mo 4+ 、Sn 4+ 、Sb 5+ 、Zr 4+ 、Al 3+ 、Fe 3+ 、Ca 2+ 、V 3+ 、Y 3+ or Ce 4+ ions, and the coating layer comprises carbon and sodium titanium phosphate. The modified layered transition metal oxide material provided by the invention has excellent stability and cycle performance.

Inventors

  • LIANG JIANDONG
  • CHEN LONG
  • YANG DAOJUN

Assignees

  • 北京希倍动力科技有限公司

Dates

Publication Date
20260508
Application Date
20251231

Claims (10)

  1. 1. The modified layered transition metal oxide material is characterized by comprising a doped modified layered transition metal oxide core and a coating layer coated on the surface of the core; The doped and modified layered transition metal oxide core is Na x Ni a Mn b M c O 2 , Wherein 0.5< x <1,0< a <0.33,0< b <0.67, a+b+c=1; M is at least three selected from Ti 4+ 、Zn 2+ 、Mg 2+ 、Cu 2+ 、W 5+ 、Mo 4+ 、Sn 4+ 、Sb 5+ 、Zr 4+ 、Al 3+ 、Fe 3+ 、Ca 2+ 、V 3+ 、Y 3+ or Ce 4+ ions; The coating layer comprises carbon and sodium titanium phosphate.
  2. 2. The modified layered transition metal oxide material of claim 1, wherein the D50 particle size of the doped modified layered transition metal oxide core is 2-5 μιη; And/or, based on the value of c being 100%, the molar content of any one ion of at least three ions selected from M is 7-80%.
  3. 3. The modified layered transition metal oxide material according to claim 1 or 2, wherein the content of the coating layer is 5 to 30% based on 100% of the total mass of the modified layered transition metal oxide material; And/or the carbon content is 0.5-3% based on 100% of the total mass of the coating layer.
  4. 4. A method of preparing a modified layered transition metal oxide material according to any one of claims 1 to 3, comprising: (1) Dispersing a Na source, a Ni source, a Mn source and an M source in a solvent, uniformly mixing, spray drying, and sintering to obtain a doped modified layered transition metal oxide core; (2) Dispersing a Na source, a Ti source, a P source and a carbon source in a solvent, and uniformly mixing to obtain sodium titanium phosphate precursor slurry; (3) And uniformly mixing the doped modified layered transition metal oxide inner core and the sodium titanium phosphate precursor slurry, and performing spray drying and calcination to obtain the modified layered transition metal oxide material.
  5. 5. The method according to claim 4, wherein the Na source is selected from any one or more of sodium carbonate, sodium bicarbonate and sodium hydroxide; and/or the Ni source is selected from any one or more of nickel monoxide, nickel sesquioxide, nickel tetraoxide, nickel hydroxide, nickel sulfate and nickel acetate; And/or the Mn source is selected from any one or more of manganese carbonate, manganese dioxide, manganomanganic oxide, manganese acetate and manganous oxide; and/or the M source is selected from any one or more of oxide, hydroxide, carbonate, oxalate, chloride, nitrate and sulfate corresponding to M element; And/or the Ti source is selected from titanium dioxide and/or titanium phosphate; and/or the P source is selected from any one or more of phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, sodium phosphate and ammonium phosphate; and/or the carbon source is selected from any one or more of glucose, sucrose, carbon nanotubes and graphite.
  6. 6. The method according to claim 4 or 5, wherein the method of mixing in step (1) is sand milling, and the size of the slurry after sand milling is less than 300 nm; and/or the spray drying temperature of step (1) is 130-200 ℃; and/or, the sintering of step (1) is performed under an air or oxygen atmosphere; And/or, the sintering temperature in the step (1) is 850-1000 ℃, and the sintering time is 8-24 hours; and/or, crushing after sintering in the step (1).
  7. 7. The method of any one of claims 4-6, wherein the method of mixing in step (2) is sanding; and/or the D50 particle size of the sodium titanium phosphate precursor slurry is 0.1-0.2 mu m; and/or, the spray drying temperature of step (3) is 150-200 ℃; and/or, the spray drying and calcining of step (3) are both carried out under an inert gas atmosphere; And/or, the temperature of the calcination in the step (3) is 600-800 ℃, and the calcination time is 8-24 hours.
  8. 8. The method according to any one of claims 4 to 7, wherein the step of mixing the doped modified layered transition metal oxide core and the sodium titanium phosphate precursor slurry in step (3) comprises mixing the doped modified layered transition metal oxide core with a dispersant and a solvent to obtain a pre-dispersed slurry, and mixing the pre-dispersed slurry and the sodium titanium phosphate precursor slurry; preferably, the dispersant is selected from polyethylene glycol and/or polyvinylpyrrolidone.
  9. 9. A positive electrode sheet, characterized in that the positive electrode sheet comprises the modified layered transition metal oxide material according to any one of claims 1 to 3 or the modified layered transition metal oxide material prepared by the preparation method according to any one of claims 4 to 8.
  10. 10. A sodium ion battery comprising the positive electrode sheet of claim 9.

Description

Modified layered transition metal oxide material and preparation method and application thereof Technical Field The invention relates to the technical field of sodium ion batteries, in particular to a modified layered transition metal oxide material, a preparation method and application thereof. Background Compared with a lithium ion battery, the sodium ion battery has higher multiplying power, wider temperature application range, lower cost and better safety, and becomes one of the important points of future new energy research. The positive electrode material, which is one of the key materials of the battery, affects the electrochemical performance of the battery. The current positive electrode material of the sodium ion battery mainly comprises layered transition metal oxide, prussian blue and polyanion positive electrode materials and the like, wherein the layered transition metal oxide has the advantages of high specific energy, abundant resources, environmental friendliness, simple and convenient process and the like, and becomes a hot spot for industrial research. However, the layered transition metal oxide has the problems of phase change under high pressure, lattice distortion caused by Jahn-Teller effect, dissolution of transition metal element caused by disproportionation of Mn 3+, poor air stability and the like, so that the cycle life of a battery applying the layered transition metal oxide is poor, and the industrial application of the layered transition metal oxide is restricted. Accordingly, it is desirable to provide a modified layered transition metal oxide to address the above-described problems. Disclosure of Invention In order to solve the technical problems, the invention provides a modified layered transition metal oxide material, and a preparation method and application thereof. The modified layered transition metal oxide material provided by the invention inhibits the Jahn-Teller effect of Mn element through doping of the medium-high entropy element, improves the structural stability, relieves high-pressure phase change, and simultaneously coats sodium titanium phosphate/carbon with a Nasicon structure on the surface of the layered transition metal oxide to further reduce the dissolution of the transition metal element, so that the stability of the modified layered transition metal oxide material and the cycle life of a battery are effectively improved. In a first aspect, the present invention provides a modified layered transition metal oxide material comprising a doped modified layered transition metal oxide core and a cladding layer coating the surface of the core; The doped and modified layered transition metal oxide core is Na xNiaMnbMcO2, Wherein 0.5< x <1,0< a <0.33,0< b <0.67, a+b+c=1; M is at least three selected from Ti4+、Zn2+、Mg2+、Cu2+、W5+、Mo4+、Sn4+、Sb5+、Zr4+、Al3+、Fe3+、Ca2+、V3+、Y3+ or Ce 4+ ions; The coating layer comprises carbon and sodium titanium phosphate. The modified layered transition metal oxide material provided by the invention utilizes the synergistic effect of the medium-high entropy element doping and the out-core sodium titanium phosphate/carbon coating layer, and effectively solves the problems of poor structural stability, poor cycle life and the like of the P2 type layered oxide positive electrode material, wherein the medium-high entropy element M is introduced to inhibit the Jahn-Teller effect of Mn element, improve the structural stability and relieve high-pressure phase change, and meanwhile, the sodium titanium phosphate in the coating layer has a Nasicon structure which has a three-dimensional framework structure, contains a sodium ion transmission channel inside and has high ion conductivity and excellent chemical stability and thermal stability, and side reactions between the inner core of the layered transition metal oxide and electrolyte can be effectively avoided, so that the modified layered transition metal oxide material provided by the invention has excellent stability and cycle performance. According to the invention, the Jahn-Teller effect of Mn element is effectively inhibited, the structural stability is improved, and the high-pressure phase change is relieved by doping at least 3 medium-high entropy elements, so that the stability and the cycle performance of the anode material are effectively improved. As a preferred embodiment of the present invention, the D50 particle size of the doped modified layered transition metal oxide core is 2-5 μm, for example 2 μm, 3 μm, 4 μm, 5 μm, etc. As a preferred embodiment of the present invention, the molar content of any one ion of the at least three ions selected from M is 7 to 80%, for example 7%, 10%, 20%, 40%, 60%, 80%, etc., preferably 20 to 60%, based on the value of c taken as 100%. As a preferable embodiment of the present invention, the content of the coating layer is 5 to 30%, for example, 5%, 10%, 15%, 20%, 25%, 30%, etc., based on 100% of the total mass of the modified layered transit