阅读说明：本技术 一种制备碳包覆二氧化钒正极材料的方法 (Method for preparing carbon-coated vanadium dioxide positive electrode material ) 是由 何倩 王成 刘显慧 韩旭然 焦云飞 吴强 陈子博 陈剑宇 应世强 李谊 马延文 于 2021-06-30 设计创作，主要内容包括：一种制备碳包覆二氧化钒正极材料的方法,将水热反应和弧光放电技术相结合,首先通过水热反应合成纯度较高、结晶性较好的二氧化钒材料,然后将二氧化钒材料均匀涂敷在不锈钢网集流体上,最后通过弧光放电技术去轰击靶材-碳源,可以得到等离子体态的碳正离子接下来用磁过滤设备对不同的等离子体态的碳正离子施加有效磁场从而可以过滤掉一些质量不均一的碳正离子,而纯度较高质量较为均一的碳正离子就被沉积到涂敷在集流体上的二氧化钒基底上从而得到具有厚度均一、纯度高的碳层的碳包覆二氧化钒复合材料。(A method for preparing carbon-coated vanadium dioxide anode material combines hydrothermal reaction and arc discharge technology, firstly synthesizes vanadium dioxide material with higher purity and better crystallinity through hydrothermal reaction, then evenly coats the vanadium dioxide material on a stainless steel mesh current collector, and finally bombards a target-carbon source through the arc discharge technology to obtain carbon cations in plasma state, and then applies an effective magnetic field to the carbon cations in different plasma states by using magnetic filtering equipment so as to filter out some carbon cations with uneven quality, and the carbon cations with higher purity and more uniform quality are deposited on a vanadium dioxide substrate coated on the current collector so as to obtain the carbon-coated vanadium dioxide composite material with a carbon layer with uniform thickness and high purity.)

1. A method for preparing carbon-coated vanadium dioxide anode material is characterized by comprising the following steps,

step S1, preparing a precursor by stirring at normal temperature, and synthesizing a vanadium dioxide material by hydrothermal reaction;

step S2, uniformly coating a vanadium dioxide material on a stainless steel mesh current collector, and bombarding a target-carbon source through an arc discharge instrument to obtain a plasma state of positive carbon ions;

and step S3, applying an effective magnetic field to the carbocations in each plasma state by using magnetic filtering equipment so as to filter the carbocations with nonuniform quality, wherein the carbocations with uniform quality are deposited on a vanadium dioxide substrate coated on a current collector, and the carbon-coated vanadium dioxide composite material is obtained.

2. The method for preparing the carbon-coated vanadium dioxide cathode material as claimed in claim 1, wherein the step S1 is to synthesize the vanadium dioxide material by the specific method,

step S11, dissolving vanadium pentoxide into water, stirring oxalic acid powder to the vanadium pentoxide at 70 ℃ to obtain a uniform mixed solution;

step S12, adding a 30% hydrogen peroxide solution into a vanadium pentoxide solution until the solution turns brown, adding absolute ethyl alcohol, transferring the solution into a polytetrafluoroethylene reaction kettle, and reacting for 5 hours at 180 ℃;

and step S13, after the hydrothermal reaction is finished, carrying out suction filtration on the product, cleaning the product by using pure water and absolute ethyl alcohol, and then drying the product at 60 ℃ for 12 hours to obtain the vanadium dioxide crystal material.

3. The method for preparing the carbon-coated vanadium dioxide cathode material as claimed in claim 1, wherein in the step S2, the dried vanadium dioxide, the conductive carbon black and the sodium carboxymethyl cellulose are mixed in a ratio of 7: 2: 1, uniformly stirring for 24 hours by taking water as a solvent, and uniformly coating the paste on a stainless steel mesh current collector for deposition after stirring.

4. The method for preparing the carbon-coated vanadium dioxide cathode material according to claim 3, wherein the deposition is carried out in a specific process,

step S21, selecting a carbon material, pressing the carbon material into a mold, and washing the mold with water and ethanol;

step S22, fixing a deposition substrate, namely a stainless steel sheet coated with vanadium dioxide, in a reaction chamber;

s23, setting arc light discharge instrument parameters, setting the voltage to be 180-210V, the current to be 1.2-2.2A and the discharge time to be 5-20 min, and converting a carbon source into carbonium ions with different masses through bombardment;

step S24, turning on a magnetic filtration power supply to apply a magnetic field, wherein the size of the magnetic field is 50-150 Wb, and distinguishing the carbocations with different masses through the action of the magnetic field so that the carbocations with the same mass can be deposited on the substrate;

and step S25, turning off arc discharge, magnetically filtering a power supply and taking out a sample.

Technical Field

The invention belongs to the technical field, and particularly relates to a method for preparing a carbon-coated vanadium dioxide anode material.

Background

The lithium ion battery which is already commercially used at present is widely applied to electronic products, power automobiles, energy storage equipment and the like due to the characteristics of high working voltage, long service life and high energy density, but the electrolyte used in the lithium ion battery is basically all combustible organic electrolyte, and once the battery releases too much heat, the battery is likely to be burnt or even explode. Therefore, research into water-based batteries with high safety, low cost, and high performance is urgently needed, and among the water-based batteries studied in many cases, the water-based zinc-ion battery is considered to be a battery system with great research prospects because the electrode potential of metal zinc is low, the price is low, and the electrolyte is stable in the water-based electrolyte. Among the cathode materials of many aqueous zinc ion batteries, vanadium-based materials have been widely studied due to their variable valence states and relatively stable crystal structures. Vanadium dioxide is a very competitive vanadium-based positive electrode material due to its large size tunnel diameter suitable for the transport of zinc ions. However, although the material has the above advantages, the practical application thereof is limited by the disadvantages of poor conductivity and easy collapse of the crystal structure during the charge and discharge processes. Therefore, at present, research workers adopt different methods to solve the problems of poor conductivity and easy collapse of the structure, and the carbon coating of the original material by the high-conductivity carbon material is an effective method, the conductivity of the material can be improved by the carbon coating, and the stability of the crystal structure can be improved by the carbon coating effect so as to prevent the collapse of the structure in the charging and discharging processes.

At present, the preparation method of the carbon-coated oxide is mainly a hydrothermal method, a carbon source is directly added into a solution, and then a carbon layer is directly grown on the surface of the vanadium oxide through hydrothermal reaction. Although the shape of the material prepared by the hydrothermal method is controllable, the carbon layer structure grown by the method is often uneven in thickness and low in purity, and meanwhile, large-scale production equipment cannot meet the requirements of high temperature and high pressure in reaction conditions.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for preparing a carbon-coated vanadium dioxide anode material, which combines hydrothermal reaction and arc discharge technology to obtain carbon-coated vanadium dioxide with a carbon layer with uniform thickness and higher purity.

The invention provides a method for preparing carbon-coated vanadium dioxide anode material, which comprises the following steps,

step S1, stirring at normal temperature to obtain a precursor, and synthesizing a vanadium dioxide material through hydrothermal reaction;

step S2, uniformly coating a vanadium dioxide material on a stainless steel current collector, bombarding a target-carbon source by an arc discharge instrument, and obtaining a plasma state of the carbon source;

and step S3, applying an effective magnetic field to each plasma carbon source by using magnetic filtering equipment so as to filter the carbocations with uneven quality, wherein the carbocations with uniform quality are deposited on a vanadium dioxide substrate coated on a current collector to obtain the carbon-coated vanadium dioxide.

As a further technical scheme of the invention, the specific method for synthesizing the vanadium dioxide material in the step S1 is that,

step S11, dissolving vanadium pentoxide into water, stirring oxalic acid powder to the vanadium pentoxide at 70 ℃ to obtain a uniform mixed solution;

step S12, adding a 30% hydrogen peroxide solution into a vanadium pentoxide solution until the solution turns brown, adding absolute ethyl alcohol, transferring the solution into a polytetrafluoroethylene reaction kettle, and reacting for 5 hours at 180 ℃;

and step S13, after the hydrothermal reaction is finished, carrying out suction filtration on the product, cleaning the product by using pure water and absolute ethyl alcohol, and then drying the product at 60 ℃ for 12 hours to obtain the vanadium dioxide crystal material.

Further, in step S2, mixing the dried vanadium dioxide, the conductive carbon black, and the sodium carboxymethylcellulose in a ratio of 7: 2: 1, uniformly stirring for 24 hours by taking water as a solvent, and uniformly coating the paste on a stainless steel mesh current collector for deposition after stirring.

Furthermore, the specific process of deposition is,

step S21, selecting a carbon material, pressing the carbon material into a mold, and washing the mold with water and ethanol;

step S22, fixing a deposition substrate, namely a stainless steel sheet coated with vanadium dioxide, in a reaction chamber;

s23, setting arc light discharge instrument parameters, setting the voltage to be 180-210V, the current to be 1.2-2.2A and the discharge time to be 5-20 min, and converting a carbon source into carbonium ions with different masses through bombardment;

step S24, turning on a magnetic filtration power supply to apply a magnetic field, wherein the size of the magnetic field is 50-150 Wb, and distinguishing the carbocations with different masses through the action of the magnetic field so that the carbocations with the same mass can be deposited on the substrate;

and step S25, turning off arc discharge, magnetically filtering a power supply and taking out a sample.

The invention has the advantages that the positive electrode material VO prepared by the method₂The coated carbon layer has controllable thickness and uniform thickness, and can maintain the cycling stability of the material in the charging and discharging processes; the magnetic filtration carbon plating technology can improve the purity of the cladding elastic layer, so that the conductivity of the cladding elastic layer is improved, and meanwhile, the deposition technology can improve the binding force between vanadium dioxide and a carbon layer, so that the stability of a vanadium dioxide crystal structure is improved, and the cycle performance of the battery can be improved.

Drawings

FIG. 1 is an SEM image of a composite material prepared in example 1 of the present invention;

FIG. 2 is a TEM image of a composite prepared in example 1 of the present invention;

FIG. 3 shows a composite material at 5A g prepared according to example 1 of the present invention^-1Cycling performance plot at current density.

Detailed Description

Example 1:

VO (vacuum oxide) by using plasma coating technology₂The preparation method of the @ C cathode material comprises the following steps of: dissolving 0.76 g of vanadium pentoxide into 100 ml, adding 0.25 g of oxalic acid powder into the vanadium pentoxide solution, and stirring the mixed aqueous solution of vanadium pentoxide and oxalic acid at 70 ℃ to obtain uniformly dispersed mixed solution. To the mixture was added 10 ml of 30% hydrogen peroxide solution and the stirring was continued until the solution became tan. 50 ml of absolute ethanol was further added, and the solution to which the absolute ethanol was added was transferred to a polytetrafluoroethylene reaction vessel and reacted at 180 ℃ for 5 hours. After the hydrothermal reaction, the product is filtered, washed by pure water and absolute ethyl alcohol and dried for 12 hours at 60 ℃. Then, 70 mg, 20 mg and 10 mg of dried vanadium dioxide, conductive carbon black and sodium carboxymethylcellulose are respectively weighed, 1500 microliters of pure water is added, and the mixture is uniformly stirred for 24 hours. After stirring, the paste is evenly coated on a cleaned stainless steel mesh current collector with the size of 4 multiplied by 5 cm. Drying in an oven at 60 deg.C, pressing conductive carbon black into a mold, pressing into a mold, washing with water and ethanol, and coating the deposition substrateThe stainless steel sheet with vanadium dioxide is fixed in the reaction chamber body. And setting parameters of an arc discharge instrument, wherein the voltage is 180-210V, the current is 1.2-2.2A, the discharge time is 5-20 min, and the carbon source is changed into the carbonium ions with different masses by utilizing an arc discharge technology. And then applying a certain magnetic field, distinguishing the carbocations with different masses through the action of the magnetic field, setting the magnitude of the program parameter magnetic field to be 50 Wb, and placing the substrate at a determined position, so that the carbocations with consistent mass can be deposited at the selected position. The arc discharge, magnetic filtration power supply was turned off and the sample was removed and taken as shown in FIGS. 1-3, SEM, TEM and at 5A g^-1Cycling performance plot at current density.

Example 2:

VO (vacuum oxide) by using plasma coating technology₂The preparation method of the @ C cathode material comprises the following steps of: dissolving 0.76 g of vanadium pentoxide into 100 ml, adding 0.25 g of oxalic acid powder into the vanadium pentoxide solution, and stirring the mixed aqueous solution of vanadium pentoxide and oxalic acid at 70 ℃ to obtain uniformly dispersed mixed solution. To the mixture was added 10 ml of 30% hydrogen peroxide solution and the stirring was continued until the solution became tan. 50 ml of absolute ethanol was further added, and the solution to which the absolute ethanol was added was transferred to a polytetrafluoroethylene reaction vessel and reacted at 180 ℃ for 5 hours. After the hydrothermal reaction, the product is filtered, washed by pure water and absolute ethyl alcohol and dried for 12 hours at 60 ℃. Then, 70 mg, 20 mg and 10 mg of dried vanadium dioxide, conductive carbon black and sodium carboxymethylcellulose are respectively weighed, 1500 microliters of pure water is added, and the mixture is uniformly stirred for 24 hours. After stirring, the paste is evenly coated on a cleaned stainless steel mesh current collector with the size of 4 multiplied by 5 cm by a liquid transfer gun. Drying in an oven at 60 deg.C, pressing carbon nanotubes into a mold, pressing into a mold, washing with water and ethanol, drying in a vacuum oven at 60 deg.C for 24 hr, and fixing the deposition substrate, i.e. stainless steel mesh sheet coated with vanadium dioxide, in a reaction chamber. Setting parameters of an arc discharge instrument, wherein the voltage is 180-210V, the current is 1.2-2.2A, the discharge time is 5-20 min, and the arc discharge technology is utilized to ensure thatThe carbon source is changed into carbocations with different masses. And then applying a certain magnetic field, distinguishing the carbocations with different masses through the action of the magnetic field, setting the magnitude of the magnetic field as 100 Wb as a program parameter, and placing the substrate at a determined position, so that the carbocations with consistent mass can be deposited at the selected position. And (5) closing the arc discharge and magnetic filtration power supply and taking out the sample.

Example 3:

VO (vacuum oxide) by using plasma coating technology₂The preparation method of the @ C cathode material comprises the following steps of: dissolving 0.76 g of vanadium pentoxide into 100 ml, adding 0.25 g of oxalic acid powder into the vanadium pentoxide solution, and stirring the mixed aqueous solution of vanadium pentoxide and oxalic acid at 70 ℃ to obtain uniformly dispersed mixed solution. To the mixture was added 10 ml of 30% hydrogen peroxide solution and stirring was continued until the solution became tan. 50 ml of absolute ethanol was further added, and the solution to which the absolute ethanol was added was transferred to a polytetrafluoroethylene reaction vessel and reacted at 180 ℃ for 5 hours. After the hydrothermal reaction, the product is filtered, washed by pure water and absolute ethyl alcohol and dried for 12 hours at 60 ℃. Then, 70 mg, 20 mg and 10 mg of dried vanadium dioxide, conductive carbon black and sodium carboxymethylcellulose are respectively weighed, 1500 microliters of pure water is added, and the mixture is uniformly stirred for 24 hours. After stirring, the paste is evenly coated on a cleaned stainless steel mesh current collector with the size of 4 multiplied by 5 cm. Drying in a 60 deg.C oven, pressing carbon nanotube into a mold, pressing into the mold, washing with water and ethanol, drying, and fixing the deposition substrate, i.e. stainless steel sheet coated with vanadium dioxide, in a reaction chamber. And setting parameters of an arc discharge instrument, wherein the voltage is 180-210V, the current is 1.2-2.2A, the discharge time is 5-20 min, and the carbon source is changed into the carbonium ions with different masses by utilizing an arc discharge technology. And then applying a certain magnetic field, distinguishing the carbocations with different masses through the action of the magnetic field, setting the magnitude of the magnetic field to be 150 Wb according to the program parameters, placing the substrate at a determined position, and depositing the carbocations with consistent mass at the selected position. Turning off arc discharge, magnetic filtering power supply, and takingAnd (6) taking out a sample.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are intended to further illustrate the principles of the invention, and that various changes and modifications may be made without departing from the spirit and scope of the invention, which is intended to be protected by the appended claims. The scope of the invention is defined by the claims and their equivalents.