A reed carbon fiber negative electrode material for a sodium ion battery and a preparation method and application thereof

Abstract

The present application belongs to the technical field of energy storage materials, and provides a reed carbon fiber negative electrode material for sodium ion batteries, and a preparation method and application thereof. The preparation method comprises the following steps: (1) pretreating reed; (2) adding the reed obtained in step (1) into a mixed solution containing tetrachloro terephthalic acid, zinc nitrate, N,N-dimethylformamide and acetic acid, and performing a solvothermal reaction, cleaning and drying to obtain uio66-4f; and (3) carbonizing the reed material coated with uio66-4f on the surface obtained in step (2) at high temperature under a protective atmosphere to obtain the preparation method of the reed carbon fiber negative electrode material for sodium ion batteries. The reed carbon fiber with a large number of mesopores is used as a carrier of the negative electrode material for sodium ion batteries, is combined with uio66-4f with fluorine atoms, can provide a large number of efficient and stable sodium ion storage active sites, improves the sodium ion transmission efficiency, at the same time, is beneficial to exposing more active sites, increases the electrochemical active area of the negative electrode material, is beneficial to the rapid penetration and diffusion of the electrolyte, and thus is beneficial to improving the specific capacity and stability of the battery negative electrode material.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of energy storage materials, and particularly relates to a reed carbon fiber negative electrode material for sodium ion batteries and a preparation method and application thereof. BACKGROUND

[0002] With the improvement of social productivity, it is expected that the global energy demand will rapidly increase in the next few decades. The energy consumed by the current social production is mainly natural fossil energy (such as oil, coal, natural gas), and the exploitation of natural energy has brought a series of problems such as ecological environment deterioration and greenhouse effect, which greatly hinders the sustainable development of ecology. Under this background, the development of clean and renewable energy is very important. Human beings have been accelerating the development of renewable energy, but due to seasonal and geographical factors, the distribution of renewable energy is uneven and intermittent, and the proportion of renewable energy that can be directly consumed is very small. Therefore, it is beneficial to the virtuous cycle of energy development to convert these renewable energy into electric energy for efficient storage.

[0003] At present, lithium ion batteries are the most widely used energy storage battery system, and with the continuous rise of the production cost of lithium ion batteries, the demand for low-cost substitutes with abundant resources has emerged as the times require, and sodium ion batteries have gradually become a potential substitute for lithium ion batteries. However, the larger sodium ion radius and slow diffusion kinetics make the graphite negative electrode material originally outstanding in lithium ion batteries cannot be directly applied in sodium ion batteries, and finding a sodium ion battery negative electrode material with satisfactory first coulomb efficiency, high-rate performance and long service life has become a new challenge for the development of sodium ion batteries.

[0004] Among all the current materials, hard carbon is the best choice for sodium-ion negative electrode material because it can accommodate sodium ions with a large interlayer distance, abundant micropores / mesopores and low redox potential. Biomass-based hard carbon is made of woody plants, grasses and vines, and their processing residues and wastes as raw materials, through physical, chemical and biological high-tech means, to process and manufacture hard carbon materials with excellent performance and high added value. At the same time, biomass-based materials are considered one of the most abundant renewable resources on earth, and have very high utilization value. Common biomass materials include reed, wood, bamboo, starch, bark, cellulose, lignin, hemicellulose, protein, chitin, etc. Among them, the cellulose content in reed is 55.82%, of which 79.97% is cellulose, 20.03% is hemicellulose, the fiber length is 1.52mm, the lignin content is 23.52%, and there are many active groups such as hydroxyl and carboxyl on the surface, and the surface active site is rich. These active groups can provide a reaction carrier for the recombination of reed and exogenous heterogeneous functional components, and the reed itself has abundant mesoporous structure, which provides a large storage space for sodium ions, making it an ideal raw material for sodium-ion battery negative materials. Efficiently utilizing reed resources not only has significant ecological significance under the background of severe natural environment in the century, but also has far-reaching economic and social benefits. However, the processing and utilization level of biomass materials in China is not high, and reed as a green material is widely used in the textile, construction and other industries. The reed residues generated during the utilization process are generally discarded in lakes or used as ordinary fuel, and there are few reports on the application of reed as a negative material for sodium-ion batteries. Not only does it cause serious resource waste, but it also causes serious environmental pollution; the existing utilization way of reed as a negative material for sodium-ion batteries also has the problem that Si contained in reed will undergo serious volume expansion (up to 300%) during sodium and desodium processes, which will lead to the decrease of mechanical stability of the negative material, and easy structure damage and pulverization, ultimately leading to the decrease of cycle life of the electrode.

[0005] Therefore, there is still a lack of a technical solution that can efficiently and stably apply reed as a biomass material in sodium electricity. SUMMARY

[0006] The technical problem to be solved by the present application is the low utilization rate of biomass materials in the prior art, which overcomes the deficiencies and shortcomings mentioned in the above background art, and provides a reed carbon fiber negative material for sodium-ion batteries and a preparation method and application thereof.

[0007] To solve the above technical problems, the technical solution provided by the present application is:

[0008] A preparation method of a reed carbon fiber negative material for sodium-ion batteries, characterized in that it comprises the following steps:

[0009] (1) pretreating the reed;

[0010] (2) adding the reed obtained in step (1) into a mixed solution containing tetrakisfluoroterephthalic acid, zinc nitrate, N,N-dimethylformamide and acetic acid, and performing a solvothermal reaction, cleaning and drying to obtain uio66-4f;

[0011] (3) carbonizing the reed material coated with uio66-4f obtained in step (2) at high temperature in a protective atmosphere to obtain a preparation method of a reed carbon fiber anode material for sodium ion batteries.

[0012] The reed is added into a solution containing tetrakisfluoroterephthalic acid and zinc nitrate, and uio66-4f is formed by a conventional synthesis and coordination method to form a metal organic framework complex. In addition, the zinc ions in uio66-4f evaporate during high-temperature carbonization, while maintaining the original framework structure, providing sites for the storage of sodium ions, and other transition metal salts are difficult to volatilize during high-temperature carbonization. N,N-dimethylformamide is a solvent with high solubility for tetrakisfluoroterephthalic acid and zinc nitrate, and acetic acid can adjust the ph value of the solution to promote the reaction.

[0013] Preferably, the pretreatment in step (1) includes soaking the reed in a sodium hydroxide solution, stirring for 2-8 hours, and cleaning and drying with deionized water.

[0014] The pretreatment is a desilication treatment for the reed, and the chemical reaction for desilication is: SiO2+2NaOH→Na2SiO3+H2O. In this reaction, solid silicon dioxide reacts with a sodium hydroxide solution to generate soluble sodium silicate (Na2SiO3) and water.

[0015] More preferably, the concentration of the sodium hydroxide solution is 1wt%-5wt%.

[0016] Preferably, the reaction temperature of the solvothermal reaction in step (2) is 120-220℃, and the reaction time is 8-48 hours.

[0017] Preferably, the mass ratio of tetrakisfluoroterephthalic acid to zinc nitrate in step (2) is 1:2-2:3, and the volume ratio of N,N-dimethylformamide to acetic acid is 5:7.

[0018] More preferably, in laboratory operations, the amount of reed added in step (2) is not more than 20g.

[0019] Preferably, the cleaning in step (2) uses ethanol, and the drying temperature is 40-80℃, and the drying time is 6-18 hours.

[0020] Preferably, the protective atmosphere in step (3) is a nitrogen or argon atmosphere, and the high-temperature carbonization is performed by two-stage sintering, the first stage sintering is heated to 350-600 DEG C at a heating rate of 2-5 DEG C / min, and the temperature is kept for 1-2 h; the second stage sintering is heated to 800-1000 DEG C at a heating rate of 2-5 DEG C / min, and the temperature is kept for 1-2 h. Here, the high-temperature carbonization is performed by two-stage sintering, because the zinc nitrate will volatilize during the carbonization process, and if the temperature is raised too fast, the material structure will collapse, and the two-stage sintering can ensure the completion of carbonization and stabilize the structure of the material.

[0021] Preferably, the reed is in a fibrous form, the fiber diameter is 8-10 um, and the reed is produced in the Dongting Lake area.

[0022] Under the same technical concept, the application further provides a reed carbon fiber negative material for a sodium ion battery, which is prepared by the preparation method of the reed carbon fiber negative material for the sodium ion battery.

[0023] Under the same technical concept, the application further provides a reed carbon fiber negative material for a sodium ion battery, which is applied in a sodium ion battery.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] (1) The application uses reed, a biomass material with a wide source, green and environmentally friendly and a large number of mesopores, as a raw material for preparing a negative electrode of a sodium ion battery, and the preparation process is simple and easy to implement, so that the high-value utilization of the biomass material can be effectively solved;

[0026] (2) The application uses reed carbon fiber with a large number of mesopores as a carrier of a negative electrode material for a sodium ion battery, and combines with uio66-4f with a fluorine atom, so that a large number of efficient and stable sodium ion storage active sites can be provided, the sodium ion transmission efficiency is improved, more active sites are exposed, the electrochemical activity area of the negative electrode material is increased, the electrolyte can be quickly penetrated and diffused, and thus the specific capacity and stability of the battery negative electrode material are improved;

[0027] (3) The micro-morphology of the reed carbon fiber negative material for a sodium ion battery is in a fibrous form, and the diameter is 8-10 um. Because the reed carbon fiber negative material for a sodium ion battery has unique anisotropy, fast axial electron transmission and radial ion diffusion characteristics, when used as a click active material, the sodium ion migration path can be greatly shortened, the sodium ions can shuttle quickly therein, the rate performance of the sodium ion battery is improved, the specific capacity is large, and the cycle stability is good;

[0028] (4) The preparation method of the present application first pretreats the reed carbon fiber, removes silicon elements therein, avoids that silicon will experience severe volume expansion in the process of sodium and sodium removal; the doping modification of organic ligand and metal ions is completed by one-step method, the introduction process of heteroatoms is simple, easy to repeat, reduces the complexity of the process, reduces the time and cost, and has significant economic advantages in large-scale production. At the same time, under the hydrothermal conditions of high temperature and high pressure, the reactant molecules have high energy and can quickly react to generate the target product. This makes the reaction efficiency higher, shortens the synthesis time and improves the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0030] Figure 1 It is a preparation method flowchart of the present application;

[0031] Figure 2 It is a scanning electron microscope (SEM) image of the reed carbon fiber negative material for sodium ion battery prepared in examples 1-4 of the present application; wherein a-e is example 1, b-f is example 2, c-g is example 3, d-h is example 4;

[0032] Figure 3 It is a first charge-discharge curve diagram of the reed carbon fiber negative material for sodium ion battery in example 1 of the present application;

[0033] Figure 4 It is a first charge-discharge curve diagram of the reed carbon fiber negative material for sodium ion battery in example 2 of the present application;

[0034] Figure 5 It is a first charge-discharge curve diagram of the reed carbon fiber negative material for sodium ion battery in example 3 of the present application;

[0035] Figure 6 It is a first charge-discharge curve diagram of the reed carbon fiber negative material for sodium ion battery in example 4 of the present application;

[0036] Figure 7 It is a first charge-discharge curve diagram of the reed fiber negative material for sodium ion battery in comparative example 1 of the present application;

[0037] Figure 8 It is a performance rate diagram of the reed carbon fiber negative material for sodium ion battery in examples 1-4 and comparative example 1 of the present application;

[0038] Figure 9 XRD pattern of reed carbon fiber negative electrode material for sodium ion battery in Example 1 of the present application;

[0039] Figure 10 Scanning electron microscope (SEM) pattern of reed carbon fiber negative electrode material for sodium ion battery in Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0040] In order to facilitate the understanding of the present application, the present application will be described in more detail and in a more complete, specific and detailed manner in conjunction with the accompanying drawings and preferred embodiments below, but the scope of protection of the present application is not limited to the following specific embodiments.

[0041] Unless otherwise defined, all the professional terms used herein have the same meaning as generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present application.

[0042] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0043] Example 1

[0044] The present embodiment provides a preparation method of reed carbon fiber negative electrode material for sodium ion battery, and the specific preparation process is shown in Figure 1 The preparation process comprises the following steps:

[0045] (1) 10 g of reed was added to 100 ml of 2% mass concentration NaOH solution and stirred at 80°C for 8 h. After the reaction was completed, it was cooled to room temperature to obtain a dark brown suspension. After centrifugal separation and drying in a 60°C drying oven for 12 h, the silicon-removed reed was obtained;

[0046] (2) The reed obtained in step (1) was added to a mixed solution containing tetrachloro terephthalic acid, zinc nitrate, N-N dimethyl formamide and acetic acid, and the mass of zinc nitrate and tetrachloro terephthalic acid was 60.0 mg and 30.0 mg, respectively; the volume of N, N-dimethyl formamide and acetic acid was 7:1 (5 ml). Solvothermal reaction was carried out at 180°C for 12-24 h, and after the reaction was completed, it was cooled to room temperature, taken out, washed with ethanol several times, and dried in a 60°C vacuum drying oven for 12 h to obtain reed material coated with uio66-4f on the surface;

[0047] (3) The uio66-4f obtained in step (2) is dried and then placed in a tubular furnace connected to nitrogen for pyrolysis carbonization, heated to 500℃ at a rate of 5℃ / min, kept for 1h, then heated to 900℃ at a rate of 5℃ / min and kept for 2h, after pyrolysis carbonization, cooled to room temperature, to obtain a reed carbon fiber negative electrode material for sodium ion batteries.

[0048] The scanning electron microscope of the reed carbon fiber negative electrode material for sodium ion batteries prepared in this example is shown in a-e of Figure 2 , and the XRD pattern is shown in Figure 9 . It can be seen that the micro-morphology of the negative electrode material is fibrous, with a diameter in the range of 8-10um, an average diameter of about 8um, and uniform size distribution. The XRD pattern of the reed carbon fiber negative electrode material for sodium ion batteries prepared in this example is shown in Figure 9 . It can be seen that, in addition to the (002) and (001) peaks of the carbon material, the strong peak appearing before 10° indicates the synthesis of uio66-4f on the reed carbon material, and the surface of the reed carbon fiber carrier is coated with uio66-4f after evaporation of zinc ions.

[0049] The application of the reed carbon fiber negative electrode material for sodium ion batteries prepared in this example includes the following steps:

[0050] Take 0.15g of the reed carbon fiber negative electrode material for sodium ion batteries prepared in this example, mix it with conductive carbon black and binder (PVDF), the mass ratio of reed carbon fiber negative electrode material, conductive carbon black and binder is 8:1:1, add the obtained mixture into N-methyl pyrrolidone solvent and stir for 6h, then coat a film on a copper foil to prepare a negative electrode sheet, use a piece of metallic sodium as the counter electrode, use a mixture of NaPF6 and Diglyme as the electrolyte, use a GF / C type glass fiber separator of Whatman as the separator, and assemble into a button cell.

[0051] The electrochemical performance of the button cell is detected, and it is found that the reed carbon fiber negative electrode material for sodium ion batteries of this example has a first discharge specific capacity of 434.9mAh / g and a charge specific capacity of 259.2mAh / g at a charge-discharge current of 200mA / g, and a first coulombic efficiency of 59.6%. The first charge-discharge curve is shown in Figure 3 . It can be seen that the voltage hysteresis effect of the charge curve and the discharge curve is small, and the rate performance is shown in Figure 8 . It can meet the demand of sodium ion batteries for high voltage and high energy density.

[0052] Example 2

[0053] This example provides a preparation method of a reed carbon fiber negative electrode material for sodium ion batteries, including the following steps:

[0054] (1) 10 g of reed is added to 100 ml of a 2% mass concentration NaOH solution, and stirred at 80°C for 8 h. After the reaction is completed, it is cooled to room temperature to obtain a dark brown suspension. After centrifugal separation and drying in a 60°C drying oven for 12 h, the desiliconized reed is obtained;

[0055] (2) The reed obtained in step (1) is added to a mixed solution containing tetrachloro terephthalic acid, zinc nitrate, N-N dimethyl formamide, and acetic acid, and the mass of zinc nitrate and tetrachloro terephthalic acid is 60.0 mg and 20.0 mg respectively; the volume of N, N-dimethyl formamide and acetic acid is 7:1 (5 ml). Solvothermal reaction is carried out at 180°C for 12-24 h. After the reaction is completed, it is cooled to room temperature, taken out, washed with ethanol several times, and placed in a 60°C vacuum drying oven for drying for 12 h to obtain the reed material coated with uio66-4f on the surface;

[0056] (3) The uio66-4f obtained in step (2) is dried and placed in a tube furnace connected to nitrogen for pyrolysis and carbonization. The temperature is raised to 500°C at a rate of 5°C / min, and after holding for 1 h, the temperature is continuously raised to 900°C at a rate of 5°C / min and held for 2 h. After pyrolysis and carbonization, it is cooled to room temperature to obtain the reed carbon fiber negative material for sodium ion battery.

[0057] The scanning electron microscope of the reed carbon fiber negative material for sodium ion battery prepared in this example is shown in Figs. b-f of Figure 2 It can be seen that the micro-morphology of the negative material presents a fibrous shape, the diameter is in the range of 8-10 um, the average diameter is about 8 um, and the size distribution is uniform, and the surface of the reed carbon fiber carrier is coated with uio66-4f after evaporation of zinc ions.

[0058] The application scheme in Example 1 is used to assemble a button cell, and the electrochemical performance of the button cell is detected. It is measured that the reed carbon fiber negative material prepared in this example has a first discharge specific capacity of 404.7 mAh / g, a charge specific capacity of 272.5 mAh / g, and a first coulombic efficiency of 67.3% when the charge and discharge current is 200 mA / g. The first charge and discharge curve is shown in Figure 4 It can be seen that the voltage hysteresis effect of the charge curve and the discharge curve is small, and the rate performance is shown in Figure 8 It can be seen that the voltage hysteresis effect of the charge curve and the discharge curve is small, and the rate performance is shown in

[0059] Example 3

[0060] A method for preparing a reed carbon fiber negative material for sodium ion battery, comprising the following steps:

[0061] (1) 10 g of reed is added to 100 ml of a 2% mass concentration NaOH solution and stirred at 80°C for 8 h. After the reaction is completed, it is cooled to room temperature to obtain a dark brown suspension. After centrifugal separation and drying in a 60°C drying oven for 12 h, the desiliconized reed is obtained;

[0062] (2) The reed obtained in step (1) is added to a mixed solution containing tetrachloro terephthalic acid, zinc nitrate, N-N dimethyl formamide and acetic acid, the mass of zinc nitrate and tetrachloro terephthalic acid is 60.0 mg and 30.0 mg respectively; the volume of N, N-dimethyl formamide and acetic acid is 5:1 (8 ml). Solvothermal reaction is carried out at 180°C for 12-24 h. After the reaction is completed, it is cooled to room temperature, taken out, washed with ethanol several times and placed in a 60°C vacuum drying oven for drying for 12 h to obtain reed material coated with uio66-4f on the surface;

[0063] (3) The uio66-4f obtained in step (2) is dried and placed in a tube furnace connected to nitrogen for pyrolysis and carbonization. The temperature is raised to 500°C at a rate of 5°C / min, and after holding for 1 h, the temperature is continuously raised to 900°C at a rate of 5°C / min and held for 2 h. After pyrolysis and carbonization, it is cooled to room temperature to obtain reed carbon fiber negative material for sodium ion battery.

[0064] The scanning electron microscope of the reed carbon fiber negative material for sodium ion battery prepared in this example is shown in Figure 2 It can be seen that the micro-morphology of the negative material presents a fibrous shape, the diameter is in the range of 8-10 um, the average diameter is about 8 um, and the size distribution is uniform. The surface of the reed carbon fiber carrier is coated with uio66-4f after evaporation of zinc ions.

[0065] The application scheme in Example 1 is used to assemble a button cell, and the electrochemical performance of the button cell is detected. It is measured that the reed carbon fiber negative material prepared in this example has a first discharge specific capacity of 399.3 mAh / g, a charge specific capacity of 256 mAh / g and a first coulombic efficiency of 64.1% when the charge and discharge current is 200 mA / g. The first charge and discharge curve is shown in Figure 5 It can be seen that the voltage hysteresis effect of the charge curve and the discharge curve is small, and the rate performance is shown in Figure 8 It can meet the demand of sodium ion battery for high voltage and high energy density.

[0066] Example 4

[0067] A method for preparing a reed carbon fiber negative material for sodium ion battery, comprising the following steps:

[0068] (1) 10 g of reed is added to 100 ml of a 2% mass concentration NaOH solution, and stirred at 80°C for 8 h. After the reaction is completed, it is cooled to room temperature to obtain a dark brown suspension. After centrifugal separation and drying in a 60°C drying oven for 12 h, the desiliconized reed is obtained;

[0069] (2) The reed obtained in step (1) is added to a mixed solution containing tetrachloro terephthalic acid, zinc nitrate, N-N dimethyl formamide, and acetic acid, and the mass of zinc nitrate and tetrachloro terephthalic acid is 60.0 mg and 20.0 mg respectively; the volume of N, N-dimethyl formamide and acetic acid is 5:1 (8 ml). Solvothermal reaction is carried out at 180°C for 12-24 h. After the reaction is completed, it is cooled to room temperature, taken out, washed with ethanol several times, and placed in a 60°C vacuum drying oven for drying for 12 h to obtain reed material coated with uio66-4f on the surface;

[0070] (3) The uio66-4f obtained in step (2) is dried and placed in a tube furnace connected to nitrogen for pyrolysis and carbonization. The temperature is raised to 500°C at a rate of 5°C / min, and after holding for 1 h, the temperature is continuously raised to 900°C at a rate of 5°C / min and held for 2 h. After pyrolysis and carbonization, it is cooled to room temperature to obtain reed carbon fiber negative material for sodium ion battery.

[0071] The scanning electron microscope of the reed carbon fiber negative material for sodium ion battery prepared in this example is shown in FIG. d-h. Figure 2 As can be seen from the figure, the micro-morphology of the negative material is fibrous, with a diameter in the range of 8-10 um, an average diameter of about 8 um, and uniform size distribution. The surface of the reed carbon fiber carrier is coated with uio66-4f after evaporation of zinc ions.

[0072] The reed carbon fiber negative material prepared in this example is assembled into a button cell according to the application scheme in Example 1, and the electrochemical performance of the button cell is detected. It is measured that when the charge and discharge current is 200 mA / g, the initial discharge specific capacity of the reed carbon fiber negative material prepared in this example is 380.7 mAh / g, the charge specific capacity is 241.9 mAh / g, and the initial coulombic efficiency is 63.5%. The initial charge and discharge curve is shown in FIG. Figure 6 As can be seen from the figure, the voltage hysteresis effect of the charge curve and the discharge curve is small, and the rate performance is shown in FIG. Figure 8 which can meet the demand of sodium ion battery for high voltage and high energy density.

[0073] Comparative Example 1

[0074] A preparation method of a reed carbon fiber negative material for sodium ion battery, comprising the following steps:

[0075] 5g of reed was weighed into a tube furnace under nitrogen for pyrolysis and carbonization, and heated to 500°C at a rate of 5°C / min, and kept for 1h, then heated to 900°C at a rate of 5°C / min and kept for 2h. After pyrolysis and carbonization, the sample was cooled to room temperature to obtain a powdered carbon material. The scanning electron microscope image of the carbon material of the present comparative example is shown in Figure 10 , wherein the spherical material is the morphology of Si element aggregation contained in the reed itself, and it can be seen that the material presents a fibrous shape.

[0076] The button cell was assembled according to the application scheme in Example 1, and the electrochemical performance of the button cell was detected. It was measured that the reed carbon fiber negative material prepared in the present example had a first discharge specific capacity of 279.2mAh / g, a charge specific capacity of 142.8mAh / g, and a first coulombic efficiency of 51.1% when the charge and discharge current was 200mA / g. The first charge and discharge curve is shown in Figure 7 , which is lower than the specific capacity data of the reed carbon fiber negative material obtained in other examples.

[0077] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any skilled person in the art can make many possible changes and modifications to the technical solutions of the present application without departing from the spirit and technical solutions of the present application, and the modified equivalent embodiments are equivalent to the above disclosed methods and technical contents. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above examples according to the technical essence of the present application, which does not deviate from the technical solutions of the present application, still belongs to the protection scope of the technical solutions of the present application.

Claims

1. A method for preparing a reed carbon fiber negative material for a sodium ion battery, characterized by, The method comprises the following steps: (1) pretreating reed; (2) adding the reed obtained in step (1) into a mixed solution containing tetrachloro terephthalic acid, zinc nitrate, N, N-dimethylformamide and acetic acid, and performing a solvothermal reaction, cleaning and drying to obtain reed material coated with uio66-4f on the surface; (3) carbonizing the reed material coated with uio66-4f on the surface obtained in step (2) at high temperature in a protective atmosphere to obtain reed carbon fiber negative material for sodium ion battery.

2. The production method according to claim 1, wherein The pretreatment in step (1) comprises: soaking the reed in a sodium hydroxide solution, stirring for 2-8 hours, cleaning with deionized water and drying.

3. The production method according to claim 1, wherein The reaction temperature of the solvothermal reaction in step (2) is 120-220 DEG C, and the reaction time is 8-48 hours.

4. The production method according to claim 1, wherein The mass ratio of tetrachloro terephthalic acid to zinc nitrate in step (2) is 1:2-2:3, and the volume ratio of N, N-dimethylformamide to acetic acid is 5:

7.

5. The production method according to claim 1, wherein The cleaning in step (2) uses ethanol, and the drying temperature is 40-80 DEG C, and the time is 6-18 hours.

6. The production method according to claim 1, wherein The protective atmosphere in step (3) is nitrogen or argon atmosphere, and the high-temperature carbonization adopts two-stage sintering, the first-stage sintering is heated to 350-600 DEG C at a heating rate of 2-5 DEG C / min, and the second-stage sintering is heated to 800-1000 DEG C at a heating rate of 2-5 DEG C / min, and the holding time is 1-2 hours.

7. The production method according to any one of claims 1 to 6, wherein The reed is in fibrous form, and the fiber diameter is 8-10 microns.

8. A reed carbon fiber anode material for sodium ion batteries, characterized by, The negative material is prepared by the method for preparing the reed carbon fiber negative material for sodium ion battery according to any one of claims 1-6, and the negative material uses reed carbon fiber as a carrier, and the surface of the reed carbon fiber is coated with uio66-4f.

9. The application of the reed carbon fiber negative material for sodium ion battery according to claim 8 in a sodium ion battery.

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