CN-121990607-A - Method for preparing titanium niobate material with assistance of ice crystal guiding-salting-out and application

Abstract

A method for preparing a titanium niobate material with the assistance of ice crystal guiding-salting-out comprises the following steps of dissolving niobium pentachloride and tetrabutyl titanate in absolute ethyl alcohol, adding a salting-out agent and a conductive additive into the absolute ethyl alcohol, uniformly mixing to obtain a precursor solution, freezing the precursor solution, then carrying out vacuum drying treatment, and calcining for 4-6 hours at 800-1000 ℃ under the protection of inert gas to obtain the titanium niobate material. According to the invention, the microstructure of the material is regulated and controlled through an innovative process, the electronic and ionic conductivity is obviously improved, the electrochemical performance of the material under the condition of high multiplying power is improved, and the technical support is provided for the wide application of the titanium niobate in the energy storage field.

Inventors

• LOU SHUAIFENG
• ZHENG HAOQING
• ZHANG YAN
• Geng Shenglu
• DONG SHENGWEI
• NING YANBIN

Assignees

• 哈尔滨工业大学

Dates

Publication Date

20260508

Application Date

20260202

Claims (10)

1. 1. The ice crystal oriented-salting-out assisted method for preparing the titanium niobate material is characterized by comprising the following steps: Firstly, dissolving niobium pentachloride and tetrabutyl titanate in absolute ethyl alcohol, adding a salting-out agent and a conductive additive into the absolute ethyl alcohol, and uniformly mixing to obtain a precursor solution; and secondly, freezing the precursor solution, then drying in vacuum, and calcining for 4-6 hours at 800-1000 ℃ under the protection of inert gas to obtain the titanium niobate material.
2. 2. The method of claim 1, wherein in the first step, the concentration of niobium ions in the precursor solution is 0.1-0.5 mol/L, and the molar ratio of niobium to titanium is 1:2-1:4.
3. 3. The method according to claim 1, wherein in the first step, niobium pentachloride and tetrabutyl titanate are respectively dissolved in absolute ethyl alcohol to form a single-component solution, and then the absolute ethyl alcohol solution of the tetrabutyl titanate is slowly dripped into the absolute ethyl alcohol solution of the niobium pentachloride at 50-60 ℃.
4. 4. The method according to claim 1, wherein in the first step, the salting-out agent comprises one or more of ammonium chloride, ammonium carbonate, ammonium sulfate and sodium citrate, the addition amount of the salting-out agent is 5% -15% of the total mass of niobium pentachloride and tetrabutyl titanate, and the conductive additive comprises one or more of carbon nanotubes, carbon fibers and graphene nanoplatelets, and the addition amount of the salting-out agent is 2% -5% of the total mass of niobium pentachloride and tetrabutyl titanate.
5. 5. The method of claim 1, wherein in the first step, the solution containing the salting-out agent and the conductive additive is subjected to high-pressure homogenization treatment in a high-pressure homogenizer to make the precursor solution clear and transparent and free of visible particulate impurities, thereby ensuring uniformity of the subsequent crystallization process.
6. 6. The method according to claim 1, wherein in the second step, the specific step of freezing treatment is that firstly, the temperature is quickly reduced to-10 to-20 ℃ at the rate of-10 to-20 ℃ per minute, a large amount of crystal nuclei are promoted to form, then the temperature is slowly reduced to-80 to-90 ℃ at the rate of-5 to-10 ℃ per hour, and the ice crystals are directionally grown for 6 to 12 hours.
7. 7. The method according to claim 1, wherein in the second step, the precursor solution is placed in a uniform magnetic field parallel to the bottom surface and having a magnetic induction of 0.5 to 1T during the freezing process to assist in alignment of the precursor.
8. 8. The method according to claim 1, wherein in the second step, the vacuum drying treatment is carried out by drying for 12 hours under the conditions of-10 ℃ and vacuum degree lower than 10Pa, heating to 20 ℃ at a rate of 1-10 ℃ per hour, and drying for 6 hours.
9. 9. The method of claim 1, wherein in the second step, high-purity argon is introduced to exhaust air, the temperature is raised, the mixed gas of argon and hydrogen with the volume ratio of 9:1 and the flow rate of 20-50 mL/min is switched to promote crystallization, the high-purity argon is introduced to prevent oxidation in the heat preservation stage, and the heat preservation temperature is 800 ℃.
10. 10. The use of the titanium niobate prepared by the method of any one of claims 1 to 9, characterized in that the titanium niobate is used as a negative electrode material of a lithium ion battery.

Description

Method for preparing titanium niobate material with assistance of ice crystal guiding-salting-out and application Technical Field The invention belongs to the field of secondary batteries, and particularly relates to a method for preparing a high-orientation consistency titanium niobate material by combining ice crystal guiding with salting-out auxiliary means and application of the high-orientation consistency titanium niobate material in the fields of energy storage batteries and the like. Background In modern society, along with rapid development of technology, an energy storage technology is important for guaranteeing stable operation of energy storage of various electronic devices, electric automobiles and large-scale power grids. As a mainstream energy storage device, the performance of the lithium ion battery directly affects the development of related industries. Currently, the market has set higher and higher requirements on the aspects of energy density, charge and discharge rate, cycle life, low-temperature performance and the like of lithium ion batteries. In the traditional lithium ion battery cathode material, graphite has the inherent defect of low lithium precipitation potential although the graphite is widely applied, so that lithium dendrites are extremely easy to generate in the battery charging and discharging process. The growth of lithium dendrite not only can cause internal short circuit of the battery, and causes the problems of rapid decay of battery capacity, shortened cycle life and the like, but also can puncture the battery diaphragm when serious, and cause electrolyte leakage, thereby causing safety accidents such as fire, explosion and the like, and greatly limiting the application expansion of the lithium ion battery in some fields with extremely high requirements on safety and stability. Compared with the traditional negative electrode, the titanium niobate (TiNb 2O7, TNO) material has theoretical specific capacity as high as 387.6 mA h g -1, and meanwhile, the working potential of the material is about 1.6V vs Li +/Li, so that the material can effectively inhibit the generation of lithium dendrites, has the advantages of safety, cycling stability and the like, and is a new ideal choice for realizing a high-power and long-service-life lithium ion battery. However, the titanium niobate material obtained under the condition of the conventional preparation process has various internal crystal forms, disordered structure, blocked electron conduction paths, complex and long ion diffusion paths, and lower electronic and ionic conductivity. The problem is that the theoretical specific capacity of the battery cannot be fully exerted under the high-rate charge-discharge and low-temperature environment, the capacity of the battery is rapidly attenuated, the performance is rapidly reduced, and the requirements of rapid response and low-temperature stable operation of the battery in practical application are difficult to meet. Therefore, developing a novel preparation process capable of effectively regulating and controlling the internal structure of the titanium niobate material, improving the electronic and ionic conductivity of the titanium niobate material and further improving the performance of the battery under various working conditions has become a key problem to be solved urgently in the current lithium ion battery field. Freeze casting has recently been used as a technique for producing functional materials based on the solidification characteristics of the materials at low temperatures. The technology mainly utilizes the directional crystallization of a solvent at low temperature to extrude solute into gaps of ice crystals, thereby inducing ordered arrangement of solute particles and forming a material with a special microstructure. The unique preparation principle provides a new way for obtaining the high-performance material with directional pore canal and gradient structure. The freezing casting technology is introduced in the preparation of the titanium niobate material, so that the limitation of the traditional preparation technology is hopeful to be broken through, and the problems of unordered internal structure, low conductivity and the like of the titanium niobate material are solved. Disclosure of Invention Based on the technical background, the invention provides a method for preparing a high-orientation consistency titanium niobate material by ice crystal guiding-salting-out assistance and application thereof in the energy storage field, and aims to regulate and control the microstructure of the material through an innovative process, remarkably improve the electronic and ionic conductivity, improve the electrochemical performance of the material under the condition of high multiplying power and provide technical support for the wide application of titanium niobate in the energy storage field. In order to achieve the above purpose, the present invention adopts th