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CN-122025604-A - Modified lithium ion battery anode material and preparation method and application thereof

CN122025604ACN 122025604 ACN122025604 ACN 122025604ACN-122025604-A

Abstract

The invention belongs to the technical field of lithium ion battery anode materials, and particularly relates to a modified lithium ion battery anode material, a preparation method and application thereof. In the invention, the doped metal elements in the core layer can reduce lithium nickel mixed arrangement, and meanwhile, the M-O bond energy is stronger, the structural stability is improved, the lattice spacing is enlarged, and the lithium ion transmission rate is improved. The solid electrolyte coating can prevent the direct contact between the core layer and the electrolyte, prevent side reaction between the core layer and the electrolyte and corrosion of decomposition products of the electrolyte to the core layer, improve stability, improve lithium ion transmission rate, build consistent chemical environment inside and on the surface through continuous modification of the same metal element, form a more uniform and stable interface, facilitate uniform transmission of lithium ions, reduce interface impedance, effectively relieve voltage attenuation and capacity attenuation, and improve rate performance and cycle life.

Inventors

  • ZHU HUALI
  • Ying Jialong
  • HUANG ZIYI
  • WANG YIYING
  • CHEN ZHAOYONG

Assignees

  • 长沙理工大学

Dates

Publication Date
20260512
Application Date
20260323

Claims (10)

  1. 1. The modified lithium ion battery anode material is characterized by comprising a core layer and a coating layer; the core layer is made of a ternary positive electrode material and doped metal elements doped in the ternary positive electrode material; the material of the coating layer is solid electrolyte; the metal elements other than lithium in the solid electrolyte are the same as the kind of the doped metal element.
  2. 2. The modified lithium ion battery positive electrode material of claim 1, wherein the ternary positive electrode material comprises LiNi x Co y Mn 1-x-y O 2 , wherein x+y is less than or equal to 1.
  3. 3. The modified lithium ion battery cathode material according to claim 1, wherein the molar amount of the doped metal element in the core layer is 0.1 to 5% of the total molar amount of the metal elements except lithium in the core layer.
  4. 4. The modified lithium ion battery cathode material of claim 1, wherein the solid state electrolyte comprises lithium aluminum titanium phosphate, lithium lanthanum zirconate, lithium lanthanum titanate, or lithium aluminum germanium phosphate.
  5. 5. The modified lithium ion battery anode material according to claim 4, wherein when the solid electrolyte is titanium aluminum lithium phosphate, the doped metal elements are titanium and aluminum, and the molar ratio of the titanium to the aluminum is 0.5-2:1; When the solid electrolyte is lithium lanthanum zirconate, the doped metal elements are zirconium and lanthanum, and the molar ratio of the zirconium to the lanthanum is 0.5-2:1; When the solid electrolyte is lithium lanthanum titanate, the doped metal elements are titanium and lanthanum, and the molar ratio of the titanium to the lanthanum is 0.5-2:1; when the solid electrolyte is lithium aluminum germanium phosphate, the doped metal elements are germanium and aluminum, and the molar ratio of the germanium to the aluminum is 0.5-2:1.
  6. 6. The modified lithium ion battery anode material according to claim 1, wherein the thickness of the coating layer is 1-10 nm, and the mass ratio of the core layer to the coating layer is 1:0.001-0.05; The particle size of the modified lithium ion battery anode material is 1-8 mu m.
  7. 7. The method for preparing the modified lithium ion battery anode material according to any one of claims 1 to 6, which is characterized by comprising the following steps: step 1, providing a precursor material corresponding to a ternary positive electrode material; Step 2, mixing raw materials corresponding to doped metal elements, the precursor material and a lithium source, and sintering to obtain a core layer material; And step 3, mixing the core layer material, the solid electrolyte and the solvent, and sequentially drying and sintering to obtain the modified lithium ion battery anode material.
  8. 8. The method according to claim 7, wherein in the step 2, the sintering includes sequentially performing a first sintering and a second sintering; the temperature of the first sintering is 300-700 ℃, and the heat preservation time is 3-7 hours; the temperature of the second sintering is 600-900 ℃ and the heat preservation time is 8-15 h, wherein the temperature of the second sintering is higher than that of the first sintering; The sintering is performed in an oxygen-containing atmosphere comprising oxygen or air.
  9. 9. The method according to claim 7, wherein in the step 3, the sintering temperature is 200-600 ℃, and the heat preservation time is 3-6 hours; The sintering is performed in an oxygen-containing atmosphere comprising oxygen or air.
  10. 10. The modified lithium ion battery positive electrode material according to any one of claims 1 to 6 or the application of the modified lithium ion battery positive electrode material prepared by the preparation method according to any one of claims 7 to 9 in a lithium ion battery.

Description

Modified lithium ion battery anode material and preparation method and application thereof Technical Field The invention belongs to the technical field of lithium ion battery anode materials, and particularly relates to a modified lithium ion battery anode material, a preparation method and application thereof. Background Common positive electrode materials of lithium ion batteries are LiCoO 2、LiMnO2 and LiNiO 2, but the materials have respective defects, and ternary LiNi xCoyMnzO2 (NCM) positive electrode materials are combined with the advantages of the three materials. The charge-discharge performance and stability of the ternary positive electrode material mainly depend on the proportion of nickel, cobalt and manganese elements in the material. The lithium ion battery is used for an electric automobile and an energy storage system, along with the continuous expansion of the market of the lithium ion battery and the increase of a power automobile, the output of the lithium ion power battery is also increased, and along with the development of the electric automobile, the low mileage cannot meet the demands of people, so that the need for finding a material with high capacity density, high stability and high safety performance is urgent. Among the numerous layered oxide cathode materials, the high-nickel ternary cathode material LiNi xCoyMnzO2 (X > 0.8) has high capacity density and high electron transfer rate, and is one of the most promising candidate materials considered to solve the high mileage of electric vehicles. However, the high nickel material also has some inherent problems such as continuous capacity attenuation caused by serious cation mixing due to too high content of Ni 2+, side reaction of electrolyte and the positive electrode material, generation of microcracks and the like, and further influences the structural stability and electrochemical performance of the positive electrode material. Disclosure of Invention The invention aims to provide a modified lithium ion battery anode material, and a preparation method and application thereof. The modified positive electrode material provided by the invention has excellent structural stability and electrochemical performance. In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a modified lithium ion battery anode material, which comprises a core layer and a coating layer; the core layer is made of a ternary positive electrode material and doped metal elements doped in the ternary positive electrode material; the material of the coating layer is solid electrolyte; the metal elements other than lithium in the solid electrolyte are the same as the kind of the doped metal element. Preferably, the ternary positive electrode material comprises LiNi xCoyMn1-x-yO2, wherein x+y is less than or equal to 1. Preferably, the mole percentage content of the doped metal element in the core layer is 0.1-5%. Preferably, the solid electrolyte comprises lithium aluminum titanium phosphate, lithium lanthanum zirconate, lithium lanthanum titanate, or lithium aluminum germanium phosphate. Preferably, when the solid electrolyte is lithium aluminum titanium phosphate, the doped metal elements are titanium and aluminum, and the molar ratio of the titanium to the aluminum is 0.5-2:1; When the solid electrolyte is lithium lanthanum zirconate, the doped metal elements are zirconium and lanthanum, and the molar ratio of the zirconium to the lanthanum is 0.5-2:1; When the solid electrolyte is lithium lanthanum titanate, the doped metal elements are titanium and lanthanum, and the molar ratio of the titanium to the lanthanum is 0.5-2:1; when the solid electrolyte is lithium aluminum germanium phosphate, the doped metal elements are germanium and aluminum, and the molar ratio of the germanium to the aluminum is 0.5-2:1. Preferably, the thickness of the coating layer is 1-10 nm, and the mass ratio of the core layer to the coating layer is 1:0.001-0.05; The particle size of the modified lithium ion battery anode material is 1-8 mu m. The invention also provides a preparation method of the modified lithium ion battery anode material, which comprises the following steps: step 1, providing a precursor material corresponding to a ternary positive electrode material; Step 2, mixing raw materials corresponding to doped metal elements, the precursor material and a lithium source, and sintering to obtain a core layer material; And step 3, mixing the core layer material, the solid electrolyte and the solvent, and sequentially drying and sintering to obtain the modified lithium ion battery anode material. Preferably, in the step 2, the sintering includes sequentially performing a first sintering and a second sintering; the temperature of the first sintering is 300-700 ℃, and the heat preservation time is 3-7 hours; the temperature of the second sintering is 600-900 ℃ and the heat preservation time is 8-15 h, where