阅读说明：本技术 一种新型锂离子电池负极材料铌基氧化物的制备方法 (Preparation method of novel niobium-based oxide as negative electrode material of lithium ion battery ) 是由 苏安邦 刘云建 杨海风 陆兆平 杨泓 于 2021-05-17 设计创作，主要内容包括：本发明涉及一种新型锂离子电池负极材料铌基氧化物的制备方法,属于锂离子电池负极材料技术领域。首先采用固相法制取前驱体Cu-2M-aNb-(0.8-0.4a)Se-4,将得到的材料置于鼓风干燥箱中进行干燥,随后将材料转移到球磨罐中,在球磨机中进行湿磨处理,球磨分散完成后将球磨罐置于烘箱中烘干。将所得的粉末置于管式炉中,于氩气气氛保护下进行烧结处理,随炉冷却到室温后得到前驱体。将得到的前驱体材料转移至坩埚中,置于玻璃管中进行煅烧处理,得到多孔片状锂离子电池负极材料。(The invention relates to a preparation method of a novel niobium-based oxide serving as a negative electrode material of a lithium ion battery, and belongs to the technical field of negative electrode materials of lithium ion batteries. Firstly, a solid phase method is adopted to prepare a precursor Cu 2 M a Nb 0.8‑0.4a Se 4 And placing the obtained material in a blast drying oven for drying, then transferring the material to a ball milling tank, carrying out wet milling treatment in a ball mill, and placing the ball milling tank in an oven for drying after the ball milling dispersion is finished. Placing the obtained powder in a tube furnace, sintering under the protection of argon atmosphere, and cooling to room temperatureThen obtaining the precursor. And transferring the obtained precursor material into a crucible, and placing the crucible in a glass tube for calcination treatment to obtain the porous sheet lithium ion battery cathode material.)

1. A preparation method of a novel lithium ion battery negative electrode material niobium-based oxide is characterized by comprising the following specific steps:

(1) firstly, a solid phase method is adopted to prepare a precursor Cu₂M_aNb_0.8-0.4aSe₄M ═ Ti, Mo, or W: weighing a niobium source, a selenium source with the excessive amount of 2-6%, a copper source and a doped metal M source according to the stoichiometric ratio, adding a liquid organic matter into the niobium source, the selenium source with the excessive amount of 2-6%, the copper source and the doped metal M source, then performing electromagnetic stirring in water bath heating, and performing ultrasonic dispersion;

(2) placing the material obtained in the step (1) in a forced air drying oven for drying, then transferring the material into a ball milling tank, carrying out wet milling treatment in a ball mill, and placing the ball milling tank in an oven for drying after the ball milling dispersion is finished;

(3) putting the powder obtained in the step (2) into a tube furnace, sintering under the protection of argon atmosphere, and cooling to room temperature along with the furnace to obtain a precursor Cu₂M_aNb_0.8-0.4aSe₄M ═ Ti, Mo, or W; wherein 0.05<x<0.2；

(4) Transferring the precursor material obtained in the step (3) into a crucible, and placing the crucible into a glass tube for calcination treatment to obtain porous flaky Cu₂M_xNb_1.2-0.4xO₅Negative electrode material, M ═ Ti, Mo or W, 0.05<x<0.2。

2. The method for preparing the novel niobium-based oxide as the negative electrode material of the lithium ion battery as claimed in claim 1, wherein in the step (1), the niobium source is niobium powder; the selenium source is selenium powder; the copper source is copper powder; the doped metal M source is tungsten powder, molybdenum powder, ammonium molybdate, sodium tungstate or titanyl sulfate; the liquid organic matter is absolute ethyl alcohol; the solid-liquid mass ratio is 0.1-0.5: 1; the water bath temperature is 35 ℃, and the electromagnetic stirring time is 3-5 h; the ultrasonic dispersion time is 30-40 min.

3. The method for preparing the novel niobium-based oxide as the negative electrode material of the lithium ion battery as claimed in claim 1, wherein in the step (2), the ball milling time is 6-8 h; the ball milling speed is 300-500 r/min.

4. The method for preparing the niobium-based oxide as the novel lithium ion battery anode material as claimed in claim 1, wherein in the step (3), the powder sintering temperature is 600-800 ℃; the heating rate is 5-15 ℃/min; the sintering time is 4-6 h.

5. The method for preparing the novel niobium-based oxide of the lithium ion battery anode material according to claim 1, wherein in the step (4), the calcination atmosphere of the precursor material is air; the heating rate is 5-10 ℃/min; the calcination temperature is 500-800 ℃, and the calcination time is 5-7 h.

Technical Field

The invention relates to a preparation method of a novel niobium-based oxide serving as a negative electrode material of a lithium ion battery, and belongs to the technical field of negative electrode materials of lithium ion batteries.

Background

Since the 21 st century, the rapid consumption of fossil fuels such as coal, petroleum, etc. caused, on the one hand, an increasingly severe environmental pollution and, on the other hand, an increased global energy crisis. Because of this, there is a pressing need for an energy storage and conversion system that is efficient, low cost, and environmentally friendly. As a typical representative of the new energy field, lithium ion batteries are widely used in various fields due to their advantages of excellent energy density, good cycle stability, light weight, low pollution, and the like. The negative electrode material is one of the key materials of the lithium ion battery, and is a research hotspot in the field. The current commonly used insertion type negative electrode material (graphite) still faces the defects of low lithium ion diffusion coefficient, thick Solid Electrolyte Interface (SEI) on the surface and the like. Particularly, graphite cathode materials are easy to react with electrolyte to form lithium dendrite at low potential, and the safety performance is seriously influenced. Therefore, finding and developing new negative electrode materials with high safety and high rate performance has become an important issue to be solved for further large-scale application of lithium ion batteries.

In recent years, Nb-based oxide (M-Nb-O) has been known to have a high reactivity with Li₄Ti₅O₁₂Similar high intercalation and deintercalation lithium potential (1.2-1.6V vs Li⁺Li), no SEI film is formed, and the safety is good; two pairs per Nb atom during charging and discharging (Nb)⁵⁺/Nb⁴⁺，Nb⁴⁺/Nb³⁺) Oxidation-reduction reaction occurs with respect to Li₄Ti₅O₁₂Shows higher specific capacity (388-402 mAhg)^–1) It draws attention and attention of scientific research personnel at home and abroad.

Based on the good electrochemical performance and application prospect of the niobium-based oxide cathode material, a plurality of preparation methods are developed at present. Mainly comprises a liquid phase method (comprising a hydrothermal method, a solvothermal method, a sol-gel method and the like), an electrostatic spinning method and a high-temperature solid phase method. Although the liquid phase method and the electrostatic spinning method can prepare niobium-based anode materials with excellent performance and special morphologies such as various nanostructures and the like, the problems of long synthesis time, low production efficiency, complex process, high equipment requirement and the like exist; meanwhile, the nano-grade material is easy to pulverize in the circulating process, and the material has poor processing performance and low energy density of the battery. Although the high-temperature solid phase method has simple process and can prepare micron-sized products, the method also has the problems of high synthesis temperature (above 1000 ℃), high energy consumption, difficult control of material morphology, poor electrochemical performance and the like. Therefore, the development of a novel method for preparing the high-performance micron-sized niobium-based oxide, which is simple and easy to implement, is not easy.

Disclosure of Invention

For the conventional Nb₂O₅Performance disadvantages and hydrothermal Nb preparation₂O₅The invention provides a method for preparing porous flaky Cu by adopting a two-step solid phase method₂M_xNb_1.2-0.4xO₅(M ═ Ti, Mo, or W) negative electrode material.

The invention comprises the following concrete steps:

1. firstly, a solid phase method is adopted to prepare a precursor Cu₂M_aNb_0.8-0.4aSe₄(M ═ Ti, Mo or W). Weighing a niobium source, a selenium source with the excessive amount of 2-6%, a copper source and a doped metal M source according to the stoichiometric ratio, adding a liquid organic matter into the niobium source, the selenium source with the excessive amount of 2-6%, the copper source and the doped metal M source, then performing electromagnetic stirring in water bath heating, and performing ultrasonic dispersion.

2. And (3) drying the material obtained in the step (1) in a forced air drying box, transferring the material into a ball milling tank, carrying out wet milling treatment in a ball mill, and drying the ball milling tank in an oven after the ball milling dispersion is finished.

3. Placing the powder obtained in the step 2 in a tube furnace, sintering under the protection of argon atmosphere, and cooling to room temperature along with the furnace to obtain a precursor Cu₂M_aNb_0.8-0.4aSe₄(M ═ Ti, Mo or W). Wherein 0.05<x<0.2。

4. Transferring the precursor material obtained in the step 3 into a crucible, and placing the crucible in a glass tube for calcination treatment to obtain porous flaky Cu₂M_xNb_1.2-0.4xO₅(M ═ Ti, Mo, or W) negative electrode material.

5. In the step 1, the niobium source is niobium powder; the selenium source is selenium powder; the copper source is copper powder; the doped metal M source is tungsten powder, molybdenum powder, ammonium molybdate, sodium tungstate or titanyl sulfate; the liquid organic matter is absolute ethyl alcohol; the solid-liquid mass ratio is 0.1-0.5: 1; the water bath temperature is 35 ℃, and the electromagnetic stirring time is 3-5 h; the ultrasonic dispersion time is 30-40 min.

6. In the step 2, the ball milling time is 6-8 h; the ball milling speed is 300-500 r/min.

7. In the step 3, the sintering temperature of the powder is 600-800 ℃; the heating rate is 5-15 ℃/min; the sintering time is 4-6 h.

8. In the step 4, the calcining atmosphere of the precursor material is air; the heating rate is 5-10 ℃/min; the calcination temperature is 500-800 ℃, and the calcination time is 5-7 h.

Compared with the existing preparation method, the preparation method has the following advantages:

1. the solid phase method has the advantages of simple process, easy synthesis, low production cost and the like, and can greatly simplify the production flow.

2. Porous flake Cu prepared by the above method₂M_xNb_1.2-0.4xO₅(M ═ Ti, Mo, W) negative electrode material, doping with Cu ion and M ion (M ═ Ti, Mo or W) resulting in Nb₂O₅The crystal lattice of (2) is distorted, so that defects are generated inside the crystal. Due to the adoption of multiple doping ions, compared with single ion doping, the Li is extracted⁺The number of the vacant sites is increased more, the lithium ion transmission path is greatly improved, and the lithium ion diffusion rate is improved. Meanwhile, the conductivity of the material is greatly increased, and the whole electrochemical performance of the material is improved.

Drawings

FIG. 1 shows Cu obtained in example 2₂Mo_0.075Nb_1.17O₅XRD pattern of the sample, in which the (001) peak appeared as the strongest peak, indicates that Nb was produced₂O₅Preferential growth, showing strong peaks indicates that the samples produced are very crystalline.

FIG. 2 shows Cu obtained in example 2₂Mo_0.075Nb_1.17O₅SEM image of sample, it can be seen that the prepared sample showed good appearancePorous hexagonal sheet shape.

FIG. 3 shows Cu obtained in example 2₂Mo_0.075Nb_1.17O₅And (3) charging and discharging curves of the sample under different multiplying factors. The result shows that the charging specific capacity of the material is obviously improved, and the material has high initial specific capacity. Wherein the specific charge capacity at 0.5C even exceeds the specific capacity of 0.2C, due to the higher capacity resulting from the activation of the active material throughout after the activation treatment.

Detailed Description

Example 1: weighing niobium powder, selenium powder, copper powder and tungsten powder according to a stoichiometric ratio, wherein the selenium is excessive by 6 percent, and the molar ratio of tungsten to niobium is 1: 23.6. adding a certain amount of absolute ethyl alcohol, wherein the solid-liquid ratio is 0.3: 1. And (3) placing the material in a water bath heating at 35 ℃ for electromagnetic stirring for 4h, performing ultrasonic dispersion for 30min, and then placing the material in a forced air drying oven for drying. And then carrying out wet grinding treatment on the material for 7h, wherein the ball milling rotation speed is n-350 r/min, and placing a ball milling tank in an oven for drying after the ball milling dispersion is finished. Then placing the mixture in an argon atmosphere to be sintered for 5 hours at 700 ℃ to obtain a precursor Cu₂W_0.05Nb_0.78Se₄The material has a heating rate of 10 ℃/min. Adding a precursor Cu₂W_0.05Nb_0.78Se₄The material is placed in a glass tube in an air state and calcined for 6 hours at 600 ℃ to obtain Cu₂W_0.05Nb_1.18O₅The temperature rise rate of the cathode material is 5 ℃/min.

Example 2: weighing niobium powder, selenium powder, copper powder and molybdenum powder according to a stoichiometric ratio, wherein the selenium is excessive by 4 percent, and the molar ratio of molybdenum to niobium is 1: 15.6. adding a certain amount of absolute ethyl alcohol, wherein the solid-liquid ratio is 0.4: 1. And (3) placing the material in a water bath heating at 35 ℃ for electromagnetic stirring for 3h, performing ultrasonic dispersion for 35min, and then placing the material in a forced air drying oven for drying. And then carrying out wet grinding treatment on the material for 8h, wherein the ball milling rotation speed is n ═ 400r/min, and placing a ball milling tank in an oven for drying after the ball milling dispersion is finished. Then placing the mixture in an argon atmosphere and sintering the mixture for 6 hours at 600 ℃ to obtain a precursor Cu₂Mo_0.075Nb_0.77Se₄The material temperature rise rate is 15 ℃/min. Adding a precursor Cu₂Mo_0.075Nb_0.77Se₄The material is placed in a glass tube in an air state and calcined for 5 hours at 700 ℃ to obtain Cu₂Mo_0.075Nb_1.17O₅The temperature rise rate of the cathode material is 10 ℃/min.

Example 3: weighing niobium powder, selenium powder, copper powder and titanyl sulfate according to a stoichiometric ratio, wherein the selenium is excessive by 3 percent, and the molar ratio of titanium to niobium is 1: 7.6. adding a certain amount of absolute ethyl alcohol, wherein the solid-liquid ratio is 0.3: 1. And (3) placing the material in a water bath heating at 35 ℃ for electromagnetic stirring for 5h, performing ultrasonic dispersion for 40min, and then placing the material in a forced air drying oven for drying. And then carrying out wet grinding treatment on the material for 6h, wherein the ball milling rotation speed is n-500 r/min, and placing a ball milling tank in an oven for drying after the ball milling dispersion is finished. Then placing the mixture in an argon atmosphere and sintering the mixture for 4 hours at 800 ℃ to obtain a precursor Cu₂Ti_0.15Nb_0.74Se₄The material has a heating rate of 12 ℃/min. Mixing Cu₂Ti_0.15Nb_0.74Se₄The material is placed in a glass tube in an air state and calcined for 7 hours at 500 ℃ to obtain Cu₂Ti_0.15Nb_1.14O₅The temperature rise rate of the cathode material is 6 ℃/min.