Preparation method of spiral carbon nanofiber

Abstract

The invention discloses a preparation method of spiral carbon nanofibers, which comprises the following specific steps: (1) carrying out magnetron sputtering on 20nm copper (the power is 30W, the gas flow is 30sccm and the time is 147s) on the surface of an aluminum foil; and (2) soaking the copper-sputtered aluminum foil in a nickel-yttrium-based catalyst with the concentration of 0.01 / 0.005 for 12 hours, and drying in a vacuum tube drying box. And (3) putting the material obtained in the step (2) in the center of a reel-to-reel plasma enhanced CVD tubular furnace, heating to 400 DEG C in an argon environment, closing argon, introducing 150 sccm of hydrogen for reduction treatment, closing hydrogen after 1 hour, opening argon, continuing heating to 600 DEG C, performing in-situ growth for 90 minutes under the conditions of 40 sccm of acetylene, 50 sccm of hydrogen and 200 sccm of argon, and then cooling to room temperature under the protection of argon. The preparation method is simple, the cost is low, and the obtained spiral carbon nanofiber can be used for a sodium ion battery negative electrode and has excellent sodium ion storage performance and cycling stability.

Description

Technical Field

[0001] The invention discloses a method for preparing spiral carbon nanofibers, and more specifically, relates to a method for preparing the spiral carbon nanofibers applied to negative electrodes of sodium ion batteries. Background Art

[0002] Currently, lithium-ion batteries have been widely used in emergency lighting and portable electronic devices, and have shown broad application prospects in electric vehicles and smart grids. Due to their high energy density and long cycle life, they are popular in applications related to energy production and storage. However, the sustainable expansion of lithium-ion batteries is severely limited due to the scarcity and uneven distribution of lithium resources.

[0003] In recent years, sodium-ion batteries have attracted increasing attention due to their abundant reserves and uniform distribution. + (equal to 1.02 ) has a significantly larger ionic radius than Li (equal to 0.76 ). Therefore, the commercial graphite-based lithium-ion battery anodes currently in use are not suitable for use in sodium-ion batteries. Therefore, a material that can reversibly intercalate Na + New sodium-ion battery anode active materials are being investigated. Extensive efforts are currently underway to develop stable, reversible and very safe candidate materials.

[0004] Carbon materials (such as carbon nanotubes, graphene, carbon nanofibers, etc.) have the advantages of high specific surface area, high electrical conductivity, high mechanical elasticity and low density, and the voids in the carbon materials can allow the penetration of electrolytes to achieve rapid Na + transmission.

[0005] Among them, carbon nanofiber materials have the advantages of good conductivity, stable structure, low cost, etc., and can therefore be used as anode materials for sodium ion batteries. The present invention prepares spiral carbon nanofibers by roll-to-roll plasma enhanced CVD, which has a simple preparation method and can make the electrode exhibit excellent cycle stability, thereby improving the safety of the battery. Summary of the invention

[0006] The present invention aims to prepare a simple sodium ion anode material, reduce costs, and commercialize sodium ion batteries as soon as possible.

[0007] To achieve the above object, the present invention adopts the following technical scheme: a method for preparing spiral carbon nanofibers, specifically comprising the following steps:

[0008] (1) Magnetron sputtering of 20 nm copper on the surface of aluminum foil (power 30 W, gas flow rate 30 sccm, time 147 s);

[0009] (2) soaking the copper-sputtered aluminum foil in a nickel-yttrium-based catalyst with a concentration of 0.01 / 0.005 for 12 hours, then drying it in a vacuum tube drying oven and taking it out after 1 hour;

[0010] (3) The material obtained in step 2 is placed in the center of a roll-to-roll plasma enhanced CVD tube furnace, heated to 400°C in an argon environment, the argon is turned off, and 150 sccm of hydrogen is introduced for reduction treatment. After 1 hour, the hydrogen is turned off, and the argon is turned on and the temperature is continued to rise to 600°C. In situ growth is carried out for 90 minutes under the conditions of 40 sccm of acetylene, 50 sccm of hydrogen, and 200 sccm of argon, and then the temperature is lowered to room temperature under the protection of argon.

[0011] The spiral carbon nanofiber material is prepared according to the preparation method and is applied to the negative electrode of a sodium ion battery.

[0012] Compared with the prior art, the method for preparing spiral carbon nanofibers described in the present invention has the following advantages:

[0013] 1) The method for preparing the spiral carbon nanofibers described in the present invention has a simple process, conforms to the concept of sustainable development, is low in cost, and is non-toxic and harmless.

[0014] 2) The present invention prepares spiral carbon nanofibers by chemical vapor deposition, and the conditions in the preparation process are controllable. The carbon nanofibers can be used as anode materials for sodium ion batteries, and have excellent conductivity and good cycle performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the SEM image of the spiral carbon nanofiber in Example 1.

[0016] Figure 2 This is the SEM image of the spiral carbon nanofiber in Example 1.

[0017] Figure 3 This is the cycle diagram of the spiral carbon nanofiber half-cell in Example 2.

[0018] Figure 4 This is the charge and discharge curve of the spiral carbon nanofiber half-cell in Example 2. DETAILED DESCRIPTION

[0019] Except for the definitions, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples are all conventional biochemical reagents unless otherwise specified; the experimental methods are all conventional methods unless otherwise specified.

[0020] The invention will be described in detail below with reference to the embodiments and the accompanying drawings.

[0021] The models and manufacturers of the equipment used in the embodiments of the present invention are as follows:

[0022] Electronic balance, model BT224S, Sartorius, Germany; triple / dual target magnetron sputtering instrument, model VTC-600-3HD / 2HD, Shenyang Kepin Automation Equipment Co., Ltd.; roll-to-roll plasma enhanced CVD, model RTR-III-80, Anhui Beiyike Equipment Technology Co., Ltd.; film punching machine, model MRXCP60, Shenzhen Kejing Co., Ltd.; glove box, model EXCEL, Ai Mingke Technology Co., Ltd.; button battery sealing machine, model MSK-110, Shenzhen Kejing Co., Ltd.; LAND battery tester, model LAND CT2001A, Wuhan Landian Electronics Co., Ltd.; scanning electron microscope, model HitachiS4800, Hitachi, Japan.

[0023] The raw material information used in each embodiment of the present invention is as follows:

[0024] Copper target, specification of 99.99%, purchased from Quanzhou Qijin New Materials Technology Co., Ltd.; nickel nitrate hexahydrate, purchased from Tianjin Fengchuan Chemical Reagent Technology Co., Ltd.; yttrium nitrate hexahydrate, purchased from Shanghai McLean Biochemical Technology Co., Ltd.; anhydrous ethanol, purchased from Tianjin Fengchuan Chemical Reagent Technology Co., Ltd.; metallic sodium, specification of battery grade, purchased from Tianjin Zhongneng Lithium Co., Ltd.; high-purity argon (Ar2), specification of 99.99%, purchased from Tianjin Huanyu Gas Co., Ltd.; high-purity hydrogen (H2), specification of 99.99%, purchased from Tianjin Huanyu Gas Co., Ltd.; acetylene, purity of 99.9%, purchased from Tianjin Huanyu Gas Co., Ltd.; glass fiber diaphragm, specification of battery grade, purchased from Cytiva, USA; battery shell, specification of CR2032, purchased from McLean Co., Ltd.; NaClO4 in EC / DEC (1:1, w / w), specification of 1 mol L-1 battery grade, purchased from Suzhou Duoduo Chemical Technology Co., Ltd.; aluminum foil, purchased from Hefei Kejing Material Technology Co., Ltd.

[0025] Example 1

[0026] A method for preparing spiral carbon nanofibers comprises the following steps:

[0027] (1) Magnetron sputtering of 20 nm copper on the surface of aluminum foil (power 30 W, gas flow rate 30 sccm, time 147 s);

[0028] (2) soaking the copper-sputtered aluminum foil in a nickel-yttrium-based catalyst with a concentration of 0.01 / 0.005 for 12 hours, and then drying it in a vacuum tube drying oven;

[0029] (3) Place the material obtained in step 2 in the center of a tube furnace, heat it to 400°C in an argon environment, turn off the argon, introduce 150sccm hydrogen for reduction treatment, and turn off the oxygen after 1 hour. Turn on the argon and continue to heat it to 600°C, grow it in situ for 90 minutes under the conditions of 40sccm acetylene, 50sccm hydrogen, and 200sccm argon, and then cool it to room temperature under the protection of argon to obtain a spiral carbon fiber material.

[0030] The electrode material prepared by the above method was tested, and the test results are shown in Figure 1 , Figure 2 .

[0031] Figure 1 , Figure 2 This is a SEM image of the spiral carbon nanofibers obtained in Example 1. From the image, it can be seen that the carbon fibers are evenly distributed and grow in a spiral shape.

[0032] Example 2

[0033] The electrode materials prepared in the above steps were assembled into a half-cell for electrochemical performance testing; the material was punched into small discs with a diameter of 12 mm using a punching machine, and assembled with a metal sodium sheet of the same size into a CR2032 button cell in a glove box filled with argon atmosphere and with a water and oxygen content of less than 0.1 ppm, and sealed with a button cell sealing machine. The electrolyte was NaCl04 inEC / DEC (1:1, w / w), with a specification of 1 mol L-1 battery grade, purchased from Suzhou Duoduo Chemical Technology Co., Ltd., and the diaphragm used a commercial glass fiber diaphragm.

[0034] Figure 3 This is a cycle efficiency diagram of the sodium ion half-cell in Example 2. As can be seen from the figure, the battery cycle is stable, and the capacity retention rate can reach more than 95% after 200 cycles.

[0035] Figure 4 This is the charge and discharge curve of the sodium ion half-battery in Example 2. The first efficiency reaches 53.5%, and the reversible capacity is high.

[0036] The present invention simplifies the preparation process of the negative electrode material of the sodium ion battery. The material has good stability, is simple and environmentally friendly, and is considered to be a very potential sodium ion battery electrode material.

[0037] The above description is only a preferred example of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing spiral carbon nanofibers, characterized in that: The specific steps include: (1) Magnetron sputtering of 20 nm copper on the surface of aluminum foil (power 30 W, gas flow rate 30 sccm, time 147 s); (2) soaking the copper-sputtered aluminum foil in a nickel-yttrium-based catalyst with a concentration of 0.01 / 0.005 for 12 hours, and then drying it in a vacuum tube drying oven; (3) The material obtained in step 2 is placed in the center of a roll-to-roll plasma enhanced CVD tube furnace, heated to 400°C in an argon environment, the argon is turned off, and 150 sccm of hydrogen is introduced for reduction treatment. After 1 hour, the hydrogen is turned off, and the argon is turned on and the temperature is continued to rise to 600°C. In situ growth is carried out for 90 minutes under the conditions of 40 sccm of acetylene, 50 sccm of hydrogen, and 200 sccm of argon, and then the temperature is lowered to room temperature under the protection of argon.

2. The method for preparing a spiral carbon nanofiber according to claim 1, characterized in that: In step 1, copper is loaded by direct current magnetron sputtering.

3. The method for preparing a spiral carbon nanofiber according to claim 1, characterized in that: The parameters of the magnetron sputtering of copper in step 1 are: power 30 W, gas flow 30 sccm, and time 147 s.

4. The method for preparing a spiral carbon nanofiber according to claim 1, characterized in that: The catalyst in step 2 is prepared from 0.01 mol / L nickel nitrate and 0.005 mol / L yttrium nitrate.

5. The method for preparing a spiral carbon nanofiber according to claim 1, characterized in that: The growth conditions in step 3 are that the spiral carbon fiber is grown in situ for 90 minutes at 600° C. under the conditions of 40 sccm of acetylene, 50 sccm of hydrogen, and 200 sccm of argon.

6. The spiral carbon nanofiber negative electrode material is prepared according to the preparation method according to any one of claims 1 to 5.

7. Application of the spiral carbon nanofiber negative electrode material obtained according to the preparation method according to any one of claims 1 to 5 in sodium ion batteries.

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