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CN-117276526-B - Rice grain-shaped TiO with adjustable length-diameter ratio2Process for the preparation of-B

CN117276526BCN 117276526 BCN117276526 BCN 117276526BCN-117276526-B

Abstract

The invention provides a preparation method of grain-shaped TiO 2 -B with adjustable length-diameter ratio, belonging to the technical field of alkali metal ion battery cathode materials. The TiO 2 -B belongs to a monoclinic system, the C2/m space group, tiO 2 -B particles are ellipsoidal, the C axis of the particles is a long axis and 7-13 nanometers, the ab axis is a short axis, the length-diameter ratio can be regulated and controlled within the range of 1.76-3.51, the synthetic purity is more than 98%, and the synthetic raw materials are low in cost and can be reused. The preparation method provided by the invention has the advantages of simple steps, strong controllability of the obtained product, large specific surface area, high purity and good electrochemical performance.

Inventors

  • LIU JILEI
  • KE JINLONG
  • GAO PENG

Assignees

  • 湖南大学

Dates

Publication Date
20260505
Application Date
20231025

Claims (7)

  1. 1. The preparation method of the grain-shaped TiO 2 -B with adjustable length-diameter ratio is characterized in that the grain-shaped TiO 2 -B belongs to a monoclinic system, C2/m space group, tiO 2 -B particles are ellipsoidal, C axes of the particles are long axes, 7-13 nanometers, ab axes are short axes, the length-diameter ratio can be adjusted and controlled within the range of 1.76-3.51, the synthetic purity is more than 98%, and the preparation method of the grain-shaped TiO 2 -B with adjustable length-diameter ratio comprises the following steps: s1, preparing a precursor solution, namely adding a titanium source into dilute sulfuric acid, and then adding glycolic acid and stirring to obtain a precursor solution A; S2, carrying out hydrothermal reaction on the precursor solution A to obtain precursor crystal nucleus with a certain [001] orientation and non-nucleated amorphous, wherein the hydrothermal reaction temperature is 180 ℃ and the time is 30 minutes; s3, after the reaction of S2 is finished, the precursor crystal nucleus obtained by S2 is continuously attached along the [001] direction by secondary hydrothermal reaction, amorphous is absorbed, a rice-shaped precursor is formed, the secondary hydrothermal reaction temperature is 140-150 ℃, and the time is 6-12 hours; And S4, calcining the rice grain-shaped precursor obtained in the step S3 in air.
  2. 2. The method for preparing grain-shaped TiO 2 -B with adjustable length-diameter ratio according to claim 1, wherein in the step S1, the concentration of dilute sulfuric acid is 0.1-0.15mol/L, the mass ratio of titanium source to dilute sulfuric acid is 0.015-0.05, and the concentration range after glycollic acid is dissolved is 1-1.5mol/L.
  3. 3. The method for preparing rice-shaped TiO 2 -B with adjustable aspect ratio according to claim 1 or 2, wherein in step S1, the titanium source includes any one or more of tetrabutyl titanate, tetraethyl titanate, isopropyl titanate, tetraisobutyl titanate, and diisopropyl di (triethanolamine) titanate.
  4. 4. The method for preparing rice-shaped TiO 2 -B with adjustable length-diameter ratio according to any of claim 1, wherein in the step S1, the glycolic acid is added after the titanium source is completely hydrolyzed, and the solution is changed from cloudiness to clarity and no peculiar smell is volatilized.
  5. 5. The method for preparing rice-grain-shaped TiO 2 -B with adjustable length-diameter ratio according to any of claim 1, wherein the raw materials in step S1 are recycled except the titanium source, and the purity of TiO 2 -B is not reduced.
  6. 6. The method for preparing grain-shaped TiO 2 -B with adjustable length-diameter ratio according to claim 1, wherein the calcining temperature in the step S4 is 370-500 ℃ and the heating rate is 2-5 ℃ per min.
  7. 7. A rice-grain TiO 2 -B prepared according to the method for preparing a rice-grain TiO 2 -B having a controllable aspect ratio according to any one of claims 1 to 6.

Description

Preparation method of rice-shaped TiO 2 -B with adjustable length-diameter ratio Technical Field The invention belongs to the technical field of alkali metal ion battery cathode materials, and particularly relates to a preparation method of rice-shaped TiO 2 -B, wherein the length-diameter ratio of particles can be regulated and controlled. Background The rapid development of power cells requires that alkali metal ion batteries (lithium ion batteries, sodium ion batteries, potassium ion batteries, etc.) have better energy density, fast charge performance, and cycle performance. TiO 2 -B is used as an oxide anode material of a lithium ion battery, has a theoretical capacity of 335mAh/g, a rapid diffusion channel of lithium ions along a B axis and a low volume expansion rate of embedded lithium, so that the TiO 2 -B has superior rate performance, cycle stability and the like to other anode materials (including graphite, silicon and other TiO 2). The lithium intercalation process of TiO 2 -B involves multiple lithium intercalation sites and lithium intercalation pathways, which makes the diffusion of lithium ions in TiO 2 -B significantly constrained by the morphology of the particles, and in particular by the dimensions of the directions associated with the lithium intercalation pathways. Several patents have disclosed methods for controlling the morphology of the particles during the preparation of TiO 2 -B. Chinese patent CN108598455B discloses a method for preparing hierarchical TiO 2 -B from ammonium fluotitanate and boric acid, and the TiO 2 -B synthesized by the method has exposed {010} crystal face, which is considered to be favorable for intercalation of lithium ions, but has obvious rutile impurity phase in the synthesized product, which makes its cycle performance poor. Chinese patent CN113511674B reports a method for synthesizing ultralong TiO 2 -B nanotubes from anatase in a high concentration NaOH solution, the TiO 2 -B has a distinct nanotube structure and hollow cavity, which is believed to be advantageous for improving the rate performance, but the high concentration NaOH, the lengthy hydrothermal time and the acid substitution time increase the cost and resource consumption of the synthesis during the synthesis. U.S. patent reports a method for preparing TiO 2 -B mesoporous spheres by spray pyrolysis granulation and NaOH template etching. Mesoporous structures are thought to facilitate electrolyte penetration and lithium ion intercalation, but this synthesis method is cumbersome and has anatase formation. In summary, the currently reported synthesis methods for morphology modulation often involve complex synthesis steps, accompanied by the formation of heterogeneous phases, and uncontrollable morphology. Disclosure of Invention The invention aims to solve the technical problems and overcome the defects in the background art, and the invention synthesizes precursor nano-particles with [001] orientation by utilizing the difference of adsorption energy of different crystal nucleus surfaces of TiO 2 -B on glycolic acid. In addition, the concentration of the glycollic acid can be regulated to regulate the degree of directional adhesion, and the calcination temperature can be regulated to regulate the degree of Ostwald ripening, so that the aspect ratio of the TiO 2 -B particles can be regulated within the range of 1.76-3.51. The preparation method provided by the invention has the advantages of simplicity, low cost, high product purity, strong controllability and excellent performance. In order to achieve the above purpose, the invention adopts the following technical scheme: the preparation method of the grain-shaped TiO2-B with adjustable length-diameter ratio specifically comprises the following steps: (1) Adding a titanium source into dilute sulfuric acid, adding glycolic acid, and stirring to obtain a precursor solution A; (2) The precursor solution A is subjected to hydrothermal reaction to obtain precursor crystal nucleus with a certain [001] orientation and non-nucleated amorphous; (3) The precursor crystal nucleus obtained in the step (2) is continuously attached along the [001] direction by secondary hydrothermal treatment, and amorphous is absorbed to form a rice-shaped precursor; (4) Calcining the rice grain-shaped precursor obtained in the step (3) in air. In the step (1), the concentration of the dilute sulfuric acid is 0.1-0.15mol/L, the mass ratio of the titanium source to the dilute sulfuric acid is 0.015-0.05, and the concentration range of the dissolved glycolic acid is 1-1.5mol/L; in the step (1), the titanium source comprises any one or more of tetrabutyl titanate, tetraethyl titanate, isopropyl titanate, tetraisobutyl titanate and di (triethanolamine) diisopropyl titanate; in the step (1), glycolic acid is added after the solution is changed from turbidity to clarity and no peculiar smell volatilizes, and the solution is hydrolyzed by co-evaporating a titanium source to obtai