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CN-115224259-B - Titanium-doped lithium nickel manganese oxide positive electrode material, preparation method and application thereof, and lithium ion battery

CN115224259BCN 115224259 BCN115224259 BCN 115224259BCN-115224259-B

Abstract

The invention provides a titanium-doped lithium nickel manganese oxide positive electrode material, a preparation method and application thereof, and a lithium ion battery. The preparation method comprises the steps of (1) mixing titanium salt and dispersion liquid containing nickel-manganese precursor under stirring to react to obtain nickel-manganese-and titanium-containing precipitate, wherein the stirring speed is 150-900 r/min, the solvent in the dispersion liquid comprises alcohol, alkaline solution and water, the volume ratio of water to alcohol is (0.05-5): 100, the mole ratio of titanium salt to nickel-manganese precursor is (3-30): 100, (2) mixing the nickel-manganese-and titanium-containing precipitate obtained in the step (1) with a lithium source to obtain intermediate mixture, calcining the intermediate mixture at the temperature of 500-1000 ℃, and the calcining time is 8-20 h. The lithium ion battery assembled by the method has the advantages of high capacity, good multiplying power performance, good cycle performance and the like.

Inventors

  • WANG SHOULIANG
  • YANG ZHAOFENG
  • GU KAI
  • ZHANG JIAHAO
  • WU ZHEN
  • LI HONG
  • LOU WENJUN
  • WANG XUFENG

Assignees

  • 宁波杉杉新材料科技有限公司

Dates

Publication Date
20260508
Application Date
20220721

Claims (19)

  1. 1. The preparation method of the titanium-doped lithium nickel manganese oxide positive electrode material is characterized by comprising the following steps of: (1) Mixing titanium salt and a dispersion liquid containing a nickel-manganese precursor under a stirring state, and reacting to obtain a precipitate containing nickel, manganese and titanium, wherein the stirring speed is 150-900 r/min, a solvent in the dispersion liquid comprises alcohol, alkaline solution and water, the volume ratio of the water to the alcohol is (0.05-5) 100, the pH value of the dispersion liquid is less than 12.5, and the molar ratio of the titanium salt to the nickel-manganese precursor is (5-20) 100; (2) Mixing the precipitate containing nickel, manganese and titanium obtained in the step (1) with a lithium source to obtain an intermediate mixture, and calcining the intermediate mixture, wherein the calcining temperature is 500-1000 ℃, the calcining time is 8-20 hours, and the titanium is doped in the bulk phase of the lithium nickel manganese oxide material and has no impurity phase on the surface of the lithium nickel manganese oxide material.
  2. 2. The method for preparing a titanium-doped lithium nickel manganese oxide positive electrode material according to claim 1, wherein the titanium salt is tetrabutyl titanate or titanium tetrachloride; and/or the nickel-manganese precursor is prepared by dissolving nickel salt, manganese salt and precipitant in a solvent according to a stoichiometric ratio, and performing hydrothermal reaction.
  3. 3. The method for preparing a titanium-doped lithium nickel manganese oxide positive electrode material according to claim 1, wherein the molar ratio of the titanium salt to the nickel manganese precursor is 10.3:100.
  4. 4. The method for preparing a titanium-doped lithium nickel manganese oxide positive electrode material according to claim 1, wherein the mixing is performed in such a manner that a titanium salt is added to a dispersion containing a nickel manganese precursor.
  5. 5. The method for preparing the titanium-doped lithium nickel manganese oxide positive electrode material according to claim 1, wherein the molecular expression of the nickel manganese precursor is Ni x Mn 2-x (CO 3 ) 2 , wherein x is more than or equal to 0.4 and less than or equal to 0.6; and/or the concentration of the nickel-manganese precursor is 0.5-2 mg/mL; And/or the alcohol is ethanol or ethylene glycol; And/or the volume ratio of the alcohol to the dispersion is (90-99.9): 100; and/or the alkaline solution is ammonia water or sodium hydroxide; and/or the pH value of the dispersion liquid containing the nickel-manganese precursor is 8-12.5; and/or the volume ratio of the water to the alcohol is (0.1-1): 100; and/or the reaction temperature is 60-90 ℃; and/or the reaction time is 4-10 h; and/or the stirring speed is 150r/min, 200 r/min, 500 r/min or 800 r/min; And/or the nickel, manganese and titanium containing precipitate is a mixture of Ni x Mn 2-x (CO 3 ) 2 and TiO 2 .
  6. 6. The preparation method of the titanium-doped lithium nickel manganese oxide positive electrode material according to claim 1, wherein the concentration of the nickel manganese precursor is 0.8-1.2 mg/mL; and/or the volume ratio of the alcohol to the dispersion is (95-99.9): 100; And/or the pH value of the dispersion liquid containing the nickel-manganese precursor is 9-11.5; and/or the volume ratio of the water to the alcohol is 0.17:100; and/or the temperature of the reaction is 80 ℃; and/or, the reaction time is 4h; And/or the stirring speed is 500-800 r/min.
  7. 7. The method for preparing a titanium-doped lithium nickel manganese oxide positive electrode material according to claim 6, wherein the concentration of the nickel manganese precursor is 1mg/mL; and/or the volume ratio of the alcohol to the dispersion is 99.7:100; and/or the pH value of the dispersion liquid containing the nickel-manganese precursor is 10.3, 10.7 or 12.1.
  8. 8. The method for preparing a titanium-doped lithium nickel manganese oxide positive electrode material according to claim 2, wherein the nickel salt is an inorganic nickel salt or an organic nickel salt; and/or the manganese salt is inorganic manganese salt or organic manganese salt; and/or the molar ratio of the nickel salt to the manganese salt is 1:3; and/or the precipitant is urea, urotropine or ammonium bicarbonate; And/or the usage amount of the precipitant is not less than the sum of the mole numbers of the nickel salt and the manganese salt; And/or the solvent is one or more of water, ethylene glycol and glycerol; and/or the total mass concentration of the nickel salt, the manganese salt and the precipitant is 0.04-0.1 g/mL; and/or the temperature of the hydrothermal reaction is 150-200 ℃; and/or the hydrothermal reaction time is 10-14 h.
  9. 9. The method for preparing a titanium-doped lithium nickel manganese oxide positive electrode material according to claim 8, wherein the nickel salt is nickel sulfate, nickel chloride, nickel nitrate or nickel acetate; and/or the manganese salt is manganese sulfate, manganese chloride, manganese nitrate or manganese acetate; and/or the total mass concentration of the nickel salt, the manganese salt and the precipitant is 0.05-0.08 g/mL; and/or the temperature of the hydrothermal reaction is 180 ℃; and/or the hydrothermal reaction time is 12 h.
  10. 10. The method for preparing a titanium-doped lithium nickel manganese oxide positive electrode material according to claim 9, wherein the total mass concentration of the nickel salt, the manganese salt and the precipitant is 0.07g/mL.
  11. 11. The method for preparing a titanium-doped lithium nickel manganese oxide positive electrode material according to claim 1, wherein the lithium source is lithium carbonate, lithium hydroxide, lithium acetate, lithium chloride or lithium nitrate; and/or the molar ratio of the lithium source to the precipitate containing nickel, manganese and titanium is 1.05:1-1.3:1; And/or the calcining temperature is 800-1000 ℃; And/or the calcination time is 9-20 h.
  12. 12. The method for preparing a titanium-doped lithium nickel manganese oxide positive electrode material according to claim 11, wherein the molar ratio of the lithium source to the precipitate containing nickel, manganese and titanium is 1.1:1 to 1.25:1; And/or the calcining temperature is 850-1000 ℃; And/or the calcination time is 10 h.
  13. 13. The method of preparing a titanium doped lithium nickel manganese oxide positive electrode material according to claim 12, wherein the molar ratio of the lithium source to the nickel, manganese and titanium containing precipitate is 1.1:1 or 1.25:1; And/or the temperature of the calcination is 800 ℃ or 900 ℃.
  14. 14. A titanium-doped lithium nickel manganese oxide positive electrode material prepared according to the preparation method of the titanium-doped lithium nickel manganese oxide positive electrode material according to any one of claims 1 to 13.
  15. 15. The titanium-doped lithium nickel manganese oxide positive electrode material according to claim 14, wherein the composition of the titanium-doped lithium nickel manganese oxide positive electrode material is LiNi x Mn 2-x-y Ti y O 4 , wherein x is more than or equal to 0.4 and less than or equal to 0.6,0.0005 and y is more than or equal to 0.01, and the titanium is doped in the bulk phase of the lithium nickel manganese oxide material and has no impurity phase on the surface of the lithium nickel manganese oxide material.
  16. 16. The titanium-doped lithium nickel manganese oxide positive electrode material according to claim 15, wherein the titanium-doped lithium nickel manganese oxide positive electrode material has a spinel structure; and/or the hetero-phase is a titanium-containing phase different from the spinel lithium nickel manganese titanate; and/or, in the titanium doped lithium nickel manganese oxide positive electrode material, the valence state of the titanium is tetravalent; And/or the titanium-doped lithium nickel manganese oxide positive electrode material is block-shaped particles with the maximum diameter length within the range of 2-10 microns.
  17. 17. The titanium-doped lithium nickel manganese oxide positive electrode material according to claim 16, wherein the hetero-phase is TiMn 2 O 4 or Li 2 TiO 3 .
  18. 18. Use of the titanium-doped lithium nickel manganese oxide positive electrode material according to any one of claims 14-17 as a positive electrode material in a lithium ion battery.
  19. 19. A lithium ion battery using the titanium-doped lithium nickel manganese oxide positive electrode material according to any one of claims 14 to 17.

Description

Titanium-doped lithium nickel manganese oxide positive electrode material, preparation method and application thereof, and lithium ion battery Technical Field The invention relates to the field of new energy materials, in particular to a titanium-doped lithium nickel manganese oxide positive electrode material, a preparation method and application thereof, and a lithium ion battery. Background Currently, lithium ion secondary batteries gradually become core energy storage devices of various electric devices due to the advantages of high energy density, no obvious memory effect, small environmental pollution, long cycle life and the like, and development of lithium ion secondary batteries with excellent electrochemical performance is an important point of current research. Among them, the positive electrode material is a key to ensure that the lithium ion secondary battery exhibits excellent performance. Currently, common cathode materials in lithium ion secondary batteries, such as lithium cobaltate, lithium manganate, lithium iron phosphate and the like, are difficult to meet the requirements of markets for high-performance lithium ion batteries, including high energy density, excellent rate performance, cycle performance and the like. Therefore, research and development of the positive electrode material with excellent electrochemical performance have great significance. Lithium nickel manganese oxide positive electrode materials are attracting attention because of their high operating voltage, high energy density and low cost. However, at high operating voltages, lattice oxygen in the lithium nickel manganese oxide material structure is unstable, and will migrate to the surface during repeated charge and discharge to cause oxidative decomposition of the electrolyte, and the decomposition product hydrogen fluoride will attack the active material, resulting in deterioration of capacity and cycle performance. In addition, after lattice oxygen is extracted from the bulk phase of the material, the stability of an oxygen frame and a diffusion channel of lithium ions of the material is poor, rapid deintercalation of lithium ions is not realized, and the rate performance is deteriorated. Therefore, enhancing the stability of oxygen atoms in the crystal lattice is a key to improving the electrochemical performance of lithium nickel manganese oxide cathode materials. Researches show that the crystal structure of the material can be effectively stabilized by introducing titanium element into the crystal structure of the material, so that the crystal structure is stabilized, the electrochemical performance is improved (J.Zhang,Q.Li,C.Ouyang,et.al,Trace doping of multiple elements enables stable battery cycling of LiCoO2 at 4.6V,Nature Energy 2019,4,594-603)., but the diffusion rate of titanium ions in the positive electrode material is lower, and the conventional doping modification means is easy to form a hetero-phase on the surface of lithium nickel manganese oxide, so that the intercalation and deintercalation of lithium ions can be hindered, and the multiplying power performance of the material is influenced. For example, the electrochemical performance of the material can be improved to a certain extent by doping titanium, but the titanium in the prepared material is doped to the same phase but forms a hetero-phase on the surface at the same time, which is unfavorable for improving the multiplying power performance (D.Kong,et.al,Ti-Gradient Doping to Stabilize Layered Surface Structure for High Performance High-Ni Oxide Cathode of Li-Ion Battery,Advanced Energy Materials,2019,1901756). Therefore, finding effective modification means to stabilize lattice oxygen by doping titanium element without introducing impurity phase on the surface becomes a difficulty and hot spot of research. In addition, in order to further improve the electrochemical performance of the lithium nickel manganese oxide positive electrode material, a reasonable structural design is necessary for the lithium nickel manganese oxide positive electrode material, wherein the large granular positive electrode material is beneficial to improving the compaction density and the mechanical strength and improving the electrochemical performance of the positive electrode material. Disclosure of Invention The invention aims to overcome the defects that in the prior art, lattice oxygen in a lithium nickel manganese oxide material structure is unstable, and a hetero-phase is easy to form on the surface after titanium ions are doped, so that the material has poor rate capability. The titanium-doped lithium nickel manganese oxide positive electrode material prepared by the method can effectively stabilize lattice oxygen by titanium ions, improves the stability of a crystal structure, is beneficial to realizing rapid deintercalation of lithium ions by the surface with low impurity content and even no impurity phase, has the characteristics of high capacity,