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CN-122025594-A - Platy mesogenic TiNb with wide temperature range2O7-xNegative electrode material of/C lithium ion battery, preparation method and application thereof

CN122025594ACN 122025594 ACN122025594 ACN 122025594ACN-122025594-A

Abstract

The invention relates to the technical field of electrode materials and lithium ion batteries, and discloses a platy mesogenic TiNb 2 O 7‑x /C lithium ion battery anode material with a wide temperature range, and a preparation method and application thereof, wherein the method comprises the following steps: acidifying layered potassium titanate KTiNbO 5 , filtering, washing, drying to obtain layered titanium niobate HTiNbO 5 , expanding in expanding agent solution, adding into carbon precursor solution to intercalate carbon precursor, hydrothermal reaction, carbonizing at 500-900 deg.c to obtain platy mesogen TiNb 2 O 7‑x /C lithium battery negative electrode material with oxygen vacancy. According to the invention, ti and Nb are reduced in the carbonization process to form oxygen vacancies, so that the introduction of carbon and oxygen vacancies synergistically improves the overall conductivity of the material, thoroughly solves the problems of uneven conductivity and transmission dynamics, and opens up a brand-new technical route for developing the next-generation lithium ion battery cathode which is high in performance, high in safety and suitable for wide-temperature-range operation.

Inventors

  • XIE KEYU
  • WANG XING
  • ZHANG KUN

Assignees

  • 西北工业大学

Dates

Publication Date
20260512
Application Date
20260304

Claims (10)

  1. 1. The preparation method of the platy mesogenic TiNb 2 O 7-x /C lithium ion battery anode material with the wide temperature range is characterized by comprising the following steps of: s1, placing layered potassium titanium niobate KTiNbO 5 in an acid solution for acidizing treatment, and then filtering, washing and drying to obtain layered titanium niobate HTiNbO 5 , placing layered titanium niobate HTiNbO 5 in an expanding agent solution for expanding treatment to obtain layered titanium niobate with an accordion structure; S2, adding the layered titanic niobic acid with the accordion structure into a carbon precursor solution, stirring to enable the carbon precursor to be intercalated into the layered titanic niobic acid with the accordion structure, then adding the carbon precursor into water for hydrothermal reaction after washing, washing again after the reaction is finished, and finally, placing a water washing product at 500-900 ℃ for carbonization treatment to obtain a platy mesogenic TiNb 2 O 7-x /C lithium battery anode material with a wide temperature range; Wherein the swelling agent is at least one of dimethylaminoethanol, methylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, ethanolamine and cetyltrimethylammonium salt, and the carbon precursor is at least one of glucose, cellulose, polyethylene glycol and sodium citrate.
  2. 2. The method for preparing the platy mesogenic TiNb 2 O 7-x /C lithium ion battery anode material with the wide temperature range according to claim 1, wherein the synthesis method of the layered potassium titanate KTiNbO 5 precursor is one of a solid phase method and a molten salt method.
  3. 3. The method for preparing the platy mesogenic TiNb 2 O 7-x /C lithium ion battery anode material with the wide temperature range according to claim 1, wherein the molten salt used in the molten salt method is one of KCl or K 2 MoO 4 , and/or the required temperature for the molten salt reaction is 800-1200 ℃ and the cooling rate is 5-300 ℃ per hour.
  4. 4. The preparation method of the platy mesogenic TiNb 2 O 7-x /C lithium ion battery anode material with the wide temperature range, which is disclosed in claim 1, is characterized in that the acid solution is hydrochloric acid solution or nitric acid solution, and the concentration is 2-8 mol/L.
  5. 5. The method for preparing the platy mesogenic TiNb 2 O 7-x /C lithium ion battery anode material with the wide temperature range according to claim 1, wherein the concentration of the expanding agent solution is 0.01-0.5 mol/L, and the concentration of the carbon precursor solution is 0.01-0.5 mol/L.
  6. 6. The method for preparing a platy mesogenic TiNb 2 O 7-x /C lithium ion battery anode material with a wide temperature range according to claim 1, wherein the temperature of the hydrothermal reaction is 150-200 ℃, and the temperature of the carbonization treatment is 700-900 ℃.
  7. 7. A platy mesogenic TiNb 2 O 7-x /C lithium ion battery anode material, characterized in that the anode material is prepared by the preparation method of any one of claims 1-6.
  8. 8. The platy mesogenic TiNb 2 O 7-x /C lithium ion battery anode material according to claim 7, wherein the platy mesogenic TiNb 2 O 7-x /C lithium ion battery anode material is a platy mesogenic material containing open tunnels, and carbon atoms of the platy mesogenic material are uniformly distributed in a TiNb 2 O 7 bulk phase.
  9. 9. The application of the platy mesogenic TiNb 2 O 7-x /C lithium ion battery anode material as an anode material in a lithium ion battery.
  10. 10. The use according to claim 9, wherein the platy mesogenic TiNb 2 O 7-x /C lithium ion battery anode material, acetylene black or Super P and polyvinylidene fluoride are mixed according to the mass ratio of 70-80:10-15:5-10, and the mixture is ground into slurry after adding solvent N-methyl pyrrolidone, and uniformly coated on a conductive metal sheet to be used as the anode of the lithium ion battery.

Description

Platy mesogenic TiNb 2O7-x/C lithium ion battery anode material with wide temperature range and preparation method and application thereof Technical Field The invention relates to the technical field of electrode materials and lithium ion batteries, in particular to a platy mesogenic TiNb 2O7-x/C lithium ion battery anode material with a wide temperature range, and a preparation method and application thereof. Background As a technological breakthrough in the aspect of lithium ion battery anode materials, a great deal of research has focused on titanium dioxide (TiO 2) -based electrode materials. The material is widely explored due to the structural stability and the safety advantage brought by higher working potential. However, when the titanium dioxide-based material is practically applied to a high-power and wide-temperature-range lithium ion battery, the titanium dioxide-based material still has obvious defects and shortcomings that firstly, the intrinsic ion conductivity is low, the diffusion kinetics of lithium ions are slow, the quick charge capacity is restricted, secondly, the theoretical specific capacity is limited (about 335 mAh g -1), the further improvement of the energy density of the battery is limited, in addition, the ion conductivity is further reduced in a low-temperature environment, the battery performance is obviously attenuated, and the interface stability between the titanium dioxide-based material and electrolyte is challenging in a high-temperature condition, and the long cycle life and the safety and the reliability are influenced. These limitations have prompted researchers to search for other material systems with a more balanced combination of properties. Among them, titanium niobium oxide (TiNb 2O7) is a very potential candidate due to its high theoretical capacity (388 mAh g -1), safe operating potential and extremely small volume expansion. However, the material also faces the bottleneck of low intrinsic electron conductivity and slow ion diffusion, and traditional surface modification strategies have difficulty penetrating into the bulk phase, excessive nanocrystallization, and sacrifice electrode density. Therefore, how to fundamentally improve the conductivity and the ion diffusion rate from the inside of the material on the basis of maintaining the intrinsic advantages thereof becomes a key to promote the practical application thereof. Disclosure of Invention In order to solve the technical problems, the main purpose of the invention is to provide a preparation method of a platy mesogenic TiNb 2O7-x/C lithium ion battery cathode material, which is characterized in that carbon atoms are uniformly inserted into a TiNb 2O7 crystal phase to form a stable mesogenic TiNb 2O7-x/C structure, and the design constructs a phase conductive network on the intrinsic scale of the material, so that not only is the electron transmission efficiency expected to be greatly improved, but also the bulk diffusion path of lithium ions can be possibly optimized. The carbonization process Ti and Nb are reduced to form oxygen vacancies, and thus, the introduction of carbon and oxygen vacancies synergistically improves the electrical conductivity of the material as a whole. The method is fundamentally different from the traditional external modification strategy, is hopeful to thoroughly solve the problems of uneven conduction and transmission dynamics while maintaining the high capacity and structural stability of TiNb 2O7, and opens up a brand-new technical route for developing the next-generation lithium ion battery cathode with high performance, high safety and wide temperature range operation. In order to achieve the above object, in a first aspect, the present invention provides a method for preparing a plate-like mesogenic TiNb 2O7-x/C lithium ion battery anode material, which is characterized by comprising the following steps: S1, placing layered potassium titanium niobate KTiNbO 5 in an acid solution for acidizing treatment, filtering, washing and drying to obtain layered titanium niobate HTiNbO 5, and placing layered titanium niobate HTiNbO 5 in an expanding agent solution for expanding treatment to obtain layered titanium niobate with an accordion structure; s2, adding the layered titanic niobic acid with the accordion structure into a carbon precursor solution, stirring to enable the carbon precursor to be intercalated into the layered titanic niobic acid with the accordion structure, then adding the layered titanic niobic acid with the accordion structure into water for hydrothermal reaction after water washing, water washing again after the reaction is finished, and finally, placing a water washing product at 500-900 ℃ for carbonization treatment to obtain a platy mesogenic TiNb 2O7-x/C lithium battery anode material with a wide temperature range and oxygen vacancies; Wherein the swelling agent is at least one of dimethylaminoethanol, methylamine, tetramethylammonium hydroxide, tetra