CN113897706A

CN113897706A - Lithium-oxygen battery electrode material and preparation method thereof

Info

Publication number: CN113897706A
Application number: CN202111084836.0A
Authority: CN
Inventors: 姜树怀; 刘格东; 杨书林
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-09-16
Filing date: 2021-09-16
Publication date: 2022-01-07

Abstract

The invention belongs to the field of electrocatalytic materials, and relates to CoWO₄A preparation method of a nanofiber lithium-oxygen battery electrode material. The method comprises the following steps: (1) preparing a certain amount of polyvinylpyrrolidone, dimethylformamide, acetic acid, cobalt acetate, ammonium metatungstate and deionized water, and fully mixing to obtain an electrostatic spinning precursor solution; (2) sucking the solution prepared in the step (1) into an electrostatic spinning injector, setting technological parameters for electrostatic spinning, covering a roller type collector with aluminum foil paper, and collecting the obtained fibers; (3) placing a product obtained by electrostatic spinning in a drying box for drying; (4) and placing the dried fiber in a muffle furnace for oxidation treatment. The invention prepares the double metal oxide CoWO by an electrostatic spinning method₄The material is made of CoWO₄Group of particlesAnd forming the porous nanofiber. The preparation method is simple, low in cost, less in time consumption and suitable for large-scale production.

Description

Lithium-oxygen battery electrode material and preparation method thereof

Technical Field

The invention belongs to the field of electrocatalytic materials, and relates to CoWO₄A preparation method of nanofiber materials.

Background

Traditional fossil fuels are non-renewable resources, and the limited energy reserves face unprecedented energy crisis for human beings. And fossil fuels release a large amount of greenhouse gases and harmful gases after being combusted, and the release of the gases has many negative effects on the environment and the physical health of human beings. Therefore, the development of new energy has become a necessary trend, and lithium-oxygen batteries have received a great deal of attention from scientists because of their ultra-high theoretical energy density.

The electrode material is a key technology for improving the performance of the lithium-oxygen battery, and the development of the electrode material with high specific capacity, good cycling stability and good rate capability is a key and difficult point for researching the lithium-oxygen battery. Transition metal oxides are considered to be one of the most promising electrode materials for lithium-oxygen batteries due to their low cost, high theoretical capacity, ease of synthesis, and the like. CoWO (cobalt oxide)₄The nano particles can provide sufficient active sites for electrochemical reaction, so that the capacity of the lithium-oxygen battery is greatly improved, the three-dimensional network structure provides sufficient reaction and storage space for reactants and products, the problem of electrode pore channel blockage is avoided, and the electro-catalysis performance of the lithium-oxygen battery is greatly improved. CoWO (cobalt oxide)₄The preparation method mainly comprises a coprecipitation method, a hydrothermal method, a spray pyrolysis method and the like, the invention develops a new method, and the CoWO is successfully prepared by the electrostatic spinning method₄And CoWO₄Has a nanofiber structure, which greatly improves the catalytic performance of the catalyst as an electrode material of a lithium-oxygen battery.

Disclosure of Invention

The invention provides a CoWO₄A preparation method of nanofiber materials. The method is simple to operate, low in cost, safe and environment-friendly, and can be used for large-scale production. When the lithium-oxygen battery anode material is used as an electrode material of a lithium-oxygen battery, the lithium-oxygen battery anode material has high specific capacity, high cycling stability and high rate property, and can obviously improve the electrochemical performance of the lithium-oxygen battery.

The invention provides a method for preparing CoWO by electrostatic spinning₄The application of the nanofiber lithium-oxygen battery cathode material.

The technical scheme of the invention is as follows: preparing polyvinylpyrrolidone, dimethylformamide, acetic acid, cobalt acetate, ammonium metatungstate and deionized water according to a certain mass and volume, fully mixing to obtain an electrostatic spinning precursor solution, sucking the electrostatic spinning precursor into an electrostatic spinning injector, performing electrostatic spinning, drying the electrostatic spinning product, and placing the dried electrostatic spinning product in a muffle furnace according to a certain volumeCalcining at a temperature and for a time to obtain CoWO₄And (3) nano fibers. The specific embodiment is as follows:

(1) weighing 1.5g of polyvinylpyrrolidone powder, dissolving the powder in 10mL of dimethylformamide, and magnetically stirring for 12h to obtain a uniform and clear solution.

(2) Adding 2mL of acetic acid into the solution obtained in the step (1), stirring for 20 minutes, adding 0.7467g of cobalt acetate powder, adding 0.7387g of ammonium metatungstate dissolved in 1mL of deionized water after the cobalt acetate powder is dispersed in the solution, and then magnetically stirring the solution for 12 hours to obtain the electrostatic spinning precursor solution.

(3) Sucking the electrostatic spinning precursor solution into an electrostatic spinning injector, setting electrostatic spinning voltage at 13kV, enabling a spinning needle to be about 230mm away from a roller collector, enabling the ambient temperature of spinning to be 30 ℃, keeping the humidity at 35% RH, enabling the feeding speed to be 1.1mL/h, covering the roller collector with aluminum foil paper, and collecting the obtained fibers.

(4) Placing the electrostatic spinning product in a drying oven for drying for 12h at 60 ℃, then placing the electrostatic spinning product in a muffle furnace for calcining at the heating rate of 2 ℃/min, and keeping the temperature at 500 ℃ for 3h to obtain CoWO₄And (3) nano fibers.

The molecular weight of the polyvinylpyrrolidone in the step (1) is 130000.

In the cobalt source and the tungsten source in the step (2), the molar ratio of cobalt element to tungsten element is 1: 1.

CoWO prepared by the invention₄The nanofiber material has a three-dimensional network structure, is large in specific surface area, simple in preparation process and short in period, and when the nanofiber material is applied to an electrode material of a lithium-oxygen battery, the capacity and the cycling stability of the battery are remarkably improved.

Drawings

FIG. 1 shows CoWO in examples 1, 2 and 3₄X-ray diffraction pattern of nanofibers.

FIGS. 2 and 3 are CoWO in example 1₄Scanning electron microscope pictures of the nanofibers at 1 ten thousand times and 5 ten thousand times respectively.

FIG. 4 shows CoWO obtained in example 1₄When the nano-fiber is used as an electrode material of a lithium-oxygen battery, the number is 1000mAg^-1The fixed capacity is 600mAhg at current density^-1Cyclic performance graph of time.

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Detailed Description

Example 1

(3) Sucking the electrostatic spinning precursor solution into an electrostatic spinning injector, setting electrostatic spinning voltage at 13kV, spinning ambient temperature at 30 ℃, keeping the humidity at 35% RH and the feeding speed at 1.1mL/h, and covering a roller collector with aluminum foil paper to collect the obtained fibers.

Example 2

(4) Placing the electrostatic spinning product in a drying oven for drying for 12h at 60 ℃, then placing the electrostatic spinning product in a muffle furnace for calcining at the heating rate of 2 ℃/min, and keeping the temperature at 600 ℃ for 3h to obtain CoWO₄And (3) nano fibers.

Example 3

(4) Placing the electrostatic spinning product in a drying oven for drying for 12h at 60 ℃, then placing the electrostatic spinning product in a muffle furnace for calcining at the heating rate of 2 ℃/min, and keeping the temperature at 700 ℃ for 3h to obtain CoWO₄And (3) nano fibers.

FIG. 1 shows CoWO prepared in examples 1, 2 and 3 of the present invention₄X-ray diffraction pattern of (a): the prepared CoWO can be seen from the diffraction pattern₄Each diffraction peak corresponds to the diffraction peak of the standard card, which indicates that the invention successfully prepares CoWO₄。

FIG. 2 and FIG. 3 show CoWO, example 1 of the present invention₄Scanning electron microscope pictures of nanofibers: from the picture, it can be seen that CoWO is a nanoparticle₄The formed nano-fiber is criss-cross, has an obvious three-dimensional reticular structure, and can be seen from a 5 ten thousand times scanning electron microscope image₄The diameter of the nano fiber is 1.5um, thereby showing that the invention successfully prepares CoWO₄And (3) nano fibers.

FIG. 3 shows CoWO prepared in example 1 of the present invention₄The nano fiber is used as an electrode material of a lithium-oxygen battery and has the volume ratio of 1000mAg^-1At a current density of 600mAg, the cutoff capacity is^-1Cyclic performance graph of time. It can be seen that CoWO₄The nano fiber has excellent electro-catalysis performance of 1000mAg when being used as an electrode material of a lithium-oxygen battery^-1Can stably circulate for 150 circles under the current density.

It should be noted that the above examples are only preferred embodiments of the present invention, and are not intended to limit the present invention, and those skilled in the art of electrocatalysis may still make modifications to the technical solutions described in the above examples, or make equivalent substitutions for some parts thereof. Any modification and equivalent arrangement of the above technical solutions, which are within the spirit and principle of the present invention, should be covered by the protection scope of the present invention.

Claims

1. CoWO (cobalt oxide tungsten trioxide)₄The preparation method of the nanofiber material is characterized by comprising the following steps of:

(1) weighing 1.5g of polyvinylpyrrolidone powder, dissolving the powder in 10mL of dimethylformamide, and magnetically stirring for 12h to obtain a uniform and clear solution;

(2) adding 2mL of acetic acid into the solution obtained in the step (1), stirring for 20 minutes, adding 0.7467g of cobalt acetate powder, adding 0.7387g of ammonium metatungstate dissolved in 1mL of deionized water after the cobalt acetate powder is dispersed in the solution, and then magnetically stirring the solution for 12 hours to obtain an electrostatic spinning precursor solution;

(3) sucking the electrostatic spinning precursor solution into an electrostatic spinning injector, setting electrostatic spinning voltage to be 13kV, enabling a spinning needle to be about 230mm away from a roller collector, keeping the ambient temperature of spinning at 30 ℃, keeping the humidity at 35% RH, and feeding at the speed of 1.1mL/h, covering the roller collector with aluminum foil paper, and collecting the obtained fibers;

(4) placing the electrostatic spinning product in a drying oven for drying for 12h at 60 ℃, then placing the electrostatic spinning product in a muffle furnace for calcining at the heating rate of 2 ℃/min, and keeping the temperature at 500 ℃ for 3h to obtain the CoWO₄And (3) nano fibers.

2. A CoWO according to claim 1₄The preparation method of the lithium-oxygen battery anode material with the nanofiber structure is characterized by comprising the following steps of: in the cobalt source and the tungsten source in the step (2), the molar ratio of the cobalt element to the tungsten element is 1: 1.

3. A CoWO according to claim 1₄The preparation method of the lithium-oxygen battery anode material with the nanofiber structure is characterized by comprising the following steps of: the electrostatic spinning voltage of the (3) is 13kV, and the feeding speed is 1.1 mL/h.

4. A CoWO according to claim 1₄The preparation method of the lithium-oxygen battery anode material with the nanofiber structure is characterized by comprising the following steps of: the heat treatment in the step (4) is to heat the electrostatic spinning product to 500 ℃ in a muffle furnace at a heating rate of 2 ℃/min and keep the temperature at 500 ℃ for 3 h.