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CN-122025574-A - Li/Mg/Si three-doped P2 type layered oxide positive electrode material, sodium ion battery positive electrode material and preparation method thereof

CN122025574ACN 122025574 ACN122025574 ACN 122025574ACN-122025574-A

Abstract

The application relates to the technical field of energy materials, in particular to a Li/Mg/Si three-doped P2 type layered oxide positive electrode material, a sodium ion battery positive electrode material and a preparation method thereof, wherein the chemical formula of the material is Na x Li a Mg b Ni c Mn d Si e O 2 , x is more than or equal to 0.60 and less than or equal to 0.80,0.01 and less than or equal to a 0.10,0.01, b is more than or equal to 0.10,0.15 and less than or equal to c is more than or equal to 0.35,0.50 and d is more than or equal to 0.75,0.01 and less than or equal to 0.12, a+b+d+e=1.00, in the material, li/Mg/Si is doped and replaced by Ni/Mn to regulate and control the electrical property of the P2 type layered oxide positive electrode material, the material has the advantages of remarkably improved high voltage reversibility, multiplying power property, long cycle life, air stability and the like, has very excellent characteristics, and provides a key material support for industrial application of sodium ion batteries.

Inventors

  • ZHAO QIAN
  • CHI CHUNLIN
  • WANG YUJUE
  • YUE QU
  • MENG YAN
  • GAO TAOTAO

Assignees

  • 成都大学

Dates

Publication Date
20260512
Application Date
20260107

Claims (11)

  1. 1. A Li/Mg/Si triple-doped P2 type layered oxide positive electrode material is characterized by comprising a chemical formula of Na x Li a Mg b Ni c Mn d Si e O 2 , wherein x is more than or equal to 0.60 and less than or equal to 0.80,0.01, a is more than or equal to 0.10,0.01, b is more than or equal to 0.10,0.15, c is more than or equal to 0.35,0.50, d is more than or equal to 0.75,0.01, e is more than or equal to 0.12, a+b+c+d+e=1.00, and in a LiMgSi triple-doped P2 type layered oxide positive electrode material Na x Li a Mg b Ni c Mn d Si e O, li/Mg/Si is subjected to Ni/Mn doping substitution so as to regulate and control the electrical property of the P2 type layered oxide positive electrode material.
  2. 2. The Li/Mg/Si triple doped P2 type layered oxide positive electrode material according to claim 1, wherein the chemical formula is Na x Li a Mg b Ni c Mn d Si e O 2 , wherein x=0.7, a=0.03, b=0.05, c=0.25, d=0.6, e=0.07, and a+b+c+d+e=1.00, i.e. Na 0.7 Li 0.03 Mg 0.05 Ni 0.25 Mn 0.6 Si 0.07 O 2 .
  3. 3. The method for preparing the Li/Mg/Si triple-doped P2 type layered oxide cathode material according to claim 1, comprising the steps of: (1) Taking a sodium source, a lithium source, a nickel source, a magnesium source, a manganese source and a silicon source, mixing materials according to Na x Li a Mg b Ni c Mn d Si e O 2 , wherein the stoichiometric ratio of sodium, nickel, manganese and doping elements lithium, magnesium and silicon is 0.60-0.80,0.01-a-0.10,0.01-b-0.10,0.15-c-0.35,0.50-d 0.75,0.01-e-0.12, and a+b+c+d+e=1.00, and mixing to obtain a mixed material precursor; (2) And carrying out sectional sintering treatment on the mixed material precursor to obtain the Li/Mg/Si three-doped P2 type layered oxide positive electrode material.
  4. 4. The method for preparing a Li/Mg/Si triple doped P2 type layered oxide positive electrode material according to claim 3, further comprising: (3) And screening the sintered material to obtain the Li/Mg/Si three-doped P2 type layered oxide positive electrode material.
  5. 5. The method for preparing a Li/Mg/Si triple-doped P2 type layered oxide cathode material according to claim 3, wherein in the step (1), the sodium source is sodium carbonate, the lithium source is lithium carbonate, the nickel source is nickel oxide, the magnesium source is magnesium oxide, the manganese source is manganese dioxide and the silicon source is silica or phenyltriethoxysilane, and the sodium source is in excess of 3 to 10mol% in terms of stoichiometric ratio.
  6. 6. The method for preparing a Li/Mg/Si triple doped P2 type layered oxide positive electrode material according to claim 3, wherein the mixing treatment in the step (1) adopts a ball milling method, specifically: Placing the raw materials into a ball milling tank, adding grinding balls with different diameters for ball milling, introducing inert gas for sealing, ball milling for 12-15 hours under the condition of 300-500rpm, and turning every 2-3 hours to obtain the mixed raw material precursor.
  7. 7. The method for preparing a Li/Mg/Si triple doped P2 layered oxide cathode material according to claim 6, wherein the ball milling tank is an agate ball milling tank, the grinding balls are zirconia grinding balls with the diameter of 3-5mm, the ball-to-material ratio is 10-12:1, and the inert gas is argon.
  8. 8. The method for preparing a Li/Mg/Si triple doped P2 type layered oxide positive electrode material according to claim 3, wherein the step of sintering comprises: Heating the precursor of the mixed material from room temperature to a low temperature region, preserving heat for a certain time, heating to a high temperature sintering region according to the same heating rate, introducing air flow, preserving heat for a certain time, maintaining the air flow, and naturally cooling to room temperature to obtain the composite material.
  9. 9. The method for preparing the Li/Mg/Si three-doped P2 layered oxide cathode material according to claim 8, wherein the low temperature range is 300-500 ℃, the first heat preservation time is 2-3 hours, the high temperature range is 700-900 ℃, the second heat preservation time is 12-15 hours, the heating rate is 3-5 ℃ per minute, and the flow rate of the introduced air is 200-300 mL per minute.
  10. 10. The method for preparing a Li/Mg/Si triple doped P2 type layered oxide positive electrode material according to claim 4, wherein the sieving specifically comprises: Screening by adopting a stainless steel screen, wherein the mesh number of the screen is 200-300 meshes, and the average grain diameter of the screened product is 2-3 mu m.
  11. 11. A positive electrode material for a sodium ion battery, characterized by comprising the Li/Mg/Si triple-doped P2 type layered oxide positive electrode material according to any one of claims 1 to 2.

Description

Li/Mg/Si three-doped P2 type layered oxide positive electrode material, sodium ion battery positive electrode material and preparation method thereof Technical Field The application relates to the technical field of energy materials, in particular to a Li/Mg/Si three-doped P2 type layered oxide positive electrode material, a sodium ion battery positive electrode material and a preparation method thereof. Background The positive electrode material is used as a core determinant of energy density, cycle stability and rate capability of a sodium ion battery, the performance optimization of the positive electrode material is a key for promoting SIBs industrialization, in various sodium ion battery positive electrode materials, P2 type layered transition metal oxides (with a general formula of NaxTMO 2, TM being transition metal elements such as Ni, mn and the like) have fast ion migration capability theoretically by virtue of a stable hexagonal crystal structure and a unique two-dimensional sodium ion transmission channel, and become a positive electrode material system with a very good prospect, however, the material faces four key bottlenecks in practical application, namely, firstly, the phase transition of irreversible P2 to O2 is easy to occur in a high voltage interval (> 4.0V vs. Na+/Na), so that lattice collapse and capacity are fast attenuated, secondly, the diffusion kinetics is slow in an embedding/deintercalation process, the capacity retention rate is low in a high rate, thirdly, the Jahn-llr (J-T) effect of high spin Mn 3+ in a low voltage interval is remarkable, the anisotropy of MnO 6 is initiated, and the material is subjected to long-term crack generation, and the electrolyte is better than the electrolyte of the electrolyte, and the electrolyte is still degraded by humidity 3, and the electrolyte is degraded by the electrolyte, and the electrolyte is better than the electrolyte, and the electrolyte is degraded by the electrolyte, and the electrolyte is degraded by the electrolyte. Therefore, the comprehensive performance of the existing P2 layered oxide cathode material can not always meet the core requirements of long cycle, high multiplying power and low cost of SIBs in a large-scale energy storage scene. Disclosure of Invention The application provides a Li/Mg/Si three-doped P2 type layered oxide positive electrode material, a sodium ion battery positive electrode material and a preparation method thereof, which are used for solving the problems of poor high voltage reversibility, insufficient high rate performance and poor cycle life of the conventional P2 type layered oxide positive electrode material. According to the first aspect of the application, the application provides a LiMgSi three-doped P2 type layered oxide positive electrode material, which has a chemical formula of Na xLiaMgbNicMndSieO2, wherein x is more than or equal to 0.60 and less than or equal to 0.80,0.01, a is more than or equal to 0.10,0.01, b is more than or equal to 0.10,0.15, c is more than or equal to 0.35,0.50, d is more than or equal to 0.75,0.01, e is more than or equal to 0.12, a+b+c+d+e=1.00, and in the Li/Mg/Si three-doped P2 type layered oxide positive electrode material Na xLiaMgbNicMndSie O, ni/Mn doping substitution is carried out on Li/Mg/Si so as to regulate and control the electrical property of the P2 type layered oxide positive electrode material. The technical scheme has the beneficial effects that the Li/Mg/Si three-doped P2 type layered oxide positive electrode material is prepared by adopting Ni/Mn in the Li/Mg/Si three-doped P2 type layered oxide positive electrode material, the electrical property of the P2 type layered oxide positive electrode material is greatly regulated and controlled and improved, and finally the material is realized in a high reversible capacity, The application provides a key positive electrode material support for industrial application of a sodium ion battery in a large-scale energy storage scene due to cooperative improvement of excellent rate performance and long cycle stability, and specifically comprises the steps that Li + mainly enters a sodium layer site due to doping of Li element, li- + is similar to the ionic radius, li-O ionic bonds stronger than Na-O are formed, interlayer spacing is effectively expanded and used as an electrostatic support, an energy barrier of sodium ion migration is obviously reduced, harmful phase transition caused by ordered Na+/vacancy is restrained, mg 2+ completely enters a transition metal layer, mn 2+ which is easy to generate Jahn-Teller distortion is replaced by priority, structural fatigue of MnO 6 octahedron is fundamentally eliminated by using an electrochemically inert d 0 configuration of the transition metal layer, si 4+ also occupies the transition metal layer due to extremely small ionic radius and high charge, TM-O bonds are obviously shortened and strengthened, the oxygen skeleton is more stable, phase transition o