Preparation method of carbon nanotube-based flexible supercapacitor electrode

Abstract

The present invention relates to a preparation method of a carbon nanotube-based flexible supercapacitor electrode, which is characterized in that a copper wire is used as an electrode substrate and serves as a copper source for an air heat treatment method to directly prepare copper oxide whiskers on the surface of the copper wire. Then, a reduction heat treatment is used to pretreat its surface and serve as a catalyst, and the growth of carbon nanotubes on the surface of the whiskers is realized by chemical vapor deposition. The preparation process includes the following steps: First, the copper wire is ultrasonically cleaned with dilute hydrochloric acid and acetone to remove surface contaminants; then, it is placed in a muffle furnace for thermal oxidation treatment to obtain copper oxide whiskers on the surface of the copper wire, and it is reductively treated with an argon / hydrogen mixed gas; finally, it is placed in a tube furnace. After the temperature is raised to the set reaction temperature, acetylene gas is introduced and maintained for a certain reaction time. After the reaction ends, the product is taken out to obtain a carbon nanotube-based flexible supercapacitor electrode.

Description

Technical Field

[0001] The present invention relates to a preparation method of a carbon nanotube-based flexible supercapacitor electrode, belonging to the field of new energy device fabrication. Background Art

[0002] To meet the increasing power supply requirements of portable electronic devices, developing a flexible supercapacitor with excellent electrochemical performance is highly challenging. Supercapacitors have advantages such as high power density, high charge-discharge rate, and environmental friendliness, and can meet the requirements of portability, flexibility, durability, and weavability of small electronic devices. They are one of the most promising new-generation energy storage devices. In particular, one-dimensional flexible supercapacitors can be directly woven into clothing, facilitating combination with other energy components to form a flexible energy storage system, opening up a new way for the development of electronic textiles. Currently, flexible fiber supercapacitors based on carbon materials (such as carbon fibers, carbon nanotubes), metal oxides (such as copper wires, nickel wires), and conductive polymers have been widely studied. However, many problems such as complex preparation processes, high costs, and low energy density have hindered their application in real life. Therefore, we urgently need to solve these problems through the synthesis and structural morphology optimization of electrode materials, as well as the innovation of preparation processes.

[0003] Among various supercapacitors using one-dimensional substrates, conductive metal wires are considered the most promising flexible current collectors for portable energy storage devices due to their high conductivity, good mechanical properties, and low cost. However, there is a certain interfacial resistance between the active material and the current collector, which will lead to a decrease in the charge transfer rate of the electrode and a shortening of the service life. In addition, the smooth surface and low specific surface area of the metal wire are not conducive to the loading and growth of electrode active substances. Therefore, how to increase its surface area to load and grow more active substances while maintaining the good conductivity of the one-dimensional metal substrate is the key to improving the electrode performance.

[0004] The present invention realizes a carbon nanotube-based flexible supercapacitor electrode by using a highly oriented copper whisker array as a conductive substrate and uniformly growing carbon nanotubes on its surface by chemical vapor deposition. The electrode has excellent specific capacitance, outstanding charge-discharge performance, and good stability, fully demonstrating the advantages of light weight, small volume, and convenient carrying of fiber supercapacitors. More importantly, its preparation process is simple, time-consuming short, and cost-effective, providing a brand-new method for the preparation of one-dimensional flexible supercapacitor electrodes. Summary of the Invention

[0005] A preparation method of a carbon nanotube-based flexible supercapacitor electrode, characterized in that, without the aid of a catalyst and a binder, the effective combination and growth of carbon nanotubes on a one-dimensional copper wire substrate are realized by using a heat treatment oxidation method and a chemical vapor deposition method. The microscopic morphology of the electrode is a highly oriented nanoarray, which has excellent electrochemical performance and has a certain degree of flexibility, durability and environmental friendliness. The method mainly includes the following steps:

[0006] (1) Take a copper wire of appropriate length, ultrasonically clean it with dilute hydrochloric acid, acetone and deionized water to remove surface contaminants, and place the copper wire in a vacuum oven at 60 °C for drying for 30 min;

[0007] (2) Place the copper wire in a porcelain boat and put it into a muffle furnace at a certain temperature for a certain time. After the reaction is completed, it is naturally cooled to room temperature to obtain a copper wire with copper oxide whiskers grown on its surface;

[0008] (3) Put the product obtained in the previous step into a tubular furnace. First, introduce an argon / hydrogen mixed gas to atmospheric pressure, keep it at a certain temperature for a certain reaction time, and then introduce acetylene gas and keep it for a certain time. When the reaction is completed, evacuate the reaction tube, take out the product after natural cooling to room temperature, and obtain a carbon nanotube-based flexible supercapacitor electrode. Description of the Drawings

[0009] Figure 1 is a low-magnification scanning electron microscope photograph of a carbon nanotube-based flexible supercapacitor electrode. From the photograph, it can be observed that the copper oxide whiskers grown with carbon nanotubes are evenly distributed and have good orientation.

[0010] Figure 2 is a high-magnification scanning electron microscope photograph of a carbon nanotube-based flexible supercapacitor electrode. The diameter of the copper oxide whiskers grown with carbon nanotubes is about 1 μm.

[0011] Figure 3 is a single copper oxide whisker grown with carbon nanotubes, and the diameter of the carbon nanotubes is 80 - 120 nm.

[0012] Figure 4 is an XPS spectrum of a carbon nanotube-based flexible supercapacitor electrode. From this spectrum, it can be known that the electrode contains copper, carbon and oxygen elements.

[0013] Figure 5 is an XPS spectrum of copper, and the binding energies of Cu 2p 1 / 2 and Cu 2p 3 / 2 are about 952.56 eV and 935.7 eV respectively, indicating that the electrode contains elemental copper; the peaks near 953.6 eV and 933.85 eV correspond to Cu 2+ in the sample, confirming the presence of CuO in the sample.

[0014] Figure 6 is the XPS spectrum of oxygen. The two peaks at 531.63 eV and 529.7 eV in this figure correspond to O in CuO 2- . Detailed implementation manners Detailed implementation manner one:

[0016] (1) Take a copper wire of appropriate length, and ultrasonically clean it with dilute hydrochloric acid, acetone and deionized water to remove surface contaminants. Place the copper wire in a vacuum oven at 60 °C and dry it for 30 min;

[0017] (2) Place the copper wire in a porcelain boat and put it into a muffle furnace at 600 °C for 1 h. After the reaction ends, naturally cool it to room temperature to obtain a copper wire with copper oxide whiskers grown on its surface;

[0018] (3) Put the product obtained in the previous step into a tubular furnace and evacuate it. First, introduce an argon / hydrogen mixed gas to atmospheric pressure and keep the tail gas overflowing. Keep it at 600 °C for 10 min for reduction treatment, and then introduce acetylene gas and keep it for 5 min. When the reaction ends, evacuate the reaction tube, naturally cool it to room temperature and then take out the product to obtain a carbon nanotube-based flexible supercapacitor electrode. Detailed implementation manner two:

[0020] (1) Take a copper wire of appropriate length, and ultrasonically clean it with dilute hydrochloric acid, acetone and deionized water to remove surface contaminants. Place the copper wire in a vacuum oven at 60 °C and dry it for 30 min;

[0021] (2) Place the copper wire in a porcelain boat and put it into a muffle furnace at 600 °C for 1 h. After the reaction ends, naturally cool it to room temperature to obtain a copper wire with copper oxide whiskers grown on its surface;

[0022] (3) Put the product obtained in the previous step into a tubular furnace and evacuate it. Then introduce an argon / hydrogen mixed gas to atmospheric pressure and keep the tail gas overflowing. Keep it at 600 °C for 20 min for reduction treatment, and then introduce acetylene gas and keep it for 10 min. When the reaction ends, evacuate the reaction tube, naturally cool it to room temperature and then take out the product to obtain a carbon nanotube-based flexible supercapacitor electrode. Detailed implementation manner three:

[0024] (1) Take a copper wire of appropriate length, and ultrasonically clean it with dilute hydrochloric acid, acetone and deionized water to remove surface contaminants. Place the copper wire in a vacuum oven at 60 °C and dry it for 30 min;

[0025] (2) Place the copper wire in a porcelain boat and put it into a muffle furnace at 600 °C for 1.5 h. After the reaction is completed, cool it naturally to room temperature to obtain a copper wire with copper oxide whiskers grown on its surface;

[0026] (3) Put the product obtained in the previous step into a tube furnace and evacuate it. Then, introduce an argon / hydrogen mixed gas to atmospheric pressure and keep the tail gas overflowing. Keep it at 700 °C for 10 min for reduction treatment, and then introduce acetylene gas and keep it for 5 min. When the reaction is completed, evacuate the reaction tube, cool it naturally to room temperature, and then take out the product to obtain a carbon nanotube-based flexible supercapacitor electrode. Specific Embodiment Four:

[0028] (1) Take a copper wire of appropriate length, and ultrasonically clean it with dilute hydrochloric acid, acetone, and deionized water to remove surface contaminants. Place the copper wire in a vacuum oven at 60 °C and dry it for 30 min;

[0029] (2) Place the copper wire in a porcelain boat and put it into a muffle furnace at 600 °C for 1.5 h. After the reaction is completed, cool it naturally to room temperature to obtain a copper wire with copper oxide whiskers grown on its surface;

[0030] (3) Put the product obtained in the previous step into a tube furnace and evacuate it. Then, introduce an argon / hydrogen mixed gas to atmospheric pressure and keep the tail gas overflowing. Keep it at 700 °C for 20 min for reduction treatment, and then introduce acetylene gas and keep it for 10 min. When the reaction is completed, evacuate the reaction tube, cool it naturally to room temperature, and then take out the product to obtain a carbon nanotube-based flexible supercapacitor electrode. Specific Embodiment Five:

[0032] (1) Take a copper wire of appropriate length, and ultrasonically clean it with dilute hydrochloric acid, acetone, and deionized water to remove surface contaminants. Place the copper wire in a vacuum oven at 60 °C and dry it for 30 min;

[0033] (2) Place the copper wire in a porcelain boat and put it into a muffle furnace at 700 °C for 1 h. After the reaction is completed, cool it naturally to room temperature to obtain a copper wire with copper oxide whiskers grown on its surface;

[0034] (3) Put the product obtained in the previous step into a tube furnace and evacuate it. Then, introduce an argon / hydrogen mixed gas to atmospheric pressure and keep the tail gas overflowing. Keep it at 600 °C for 10 min for reduction treatment, and then introduce acetylene gas and keep it for 5 min. When the reaction is completed, evacuate the reaction tube, cool it naturally to room temperature, and then take out the product to obtain a carbon nanotube-based flexible supercapacitor electrode. Specific Embodiment Six:

[0036] (1) Take a copper wire of appropriate length, and ultrasonically clean it with dilute hydrochloric acid, acetone, and deionized water to remove surface contaminants. Place the copper wire in a vacuum oven at 60 °C and dry it for 30 min;

[0037] (2) Place the copper wire in a porcelain boat and put it into a muffle furnace at 700 °C for 1 h. After the reaction ends, naturally cool it to room temperature to obtain a copper wire with copper oxide whiskers grown on its surface;

[0038] (3) Put the product obtained in the previous step into a tubular furnace and evacuate it. Then, introduce an argon / hydrogen mixed gas to atmospheric pressure and keep the tail gas overflowing. Keep it at 600 °C for 20 min for reduction treatment, and then introduce acetylene gas and keep it for 10 min. When the reaction ends, evacuate the reaction tube, naturally cool it to room temperature, and then take out the product to obtain a carbon nanotube-based flexible supercapacitor electrode. Specific embodiment seven:

[0040] (1) Take a copper wire of appropriate length, and ultrasonically clean it with dilute hydrochloric acid, acetone, and deionized water to remove surface contaminants. Place the copper wire in a vacuum oven at 60 °C and dry it for 30 min;

[0041] (2) Place the copper wire in a porcelain boat and put it into a muffle furnace at 700 °C for 1.5 h. After the reaction ends, naturally cool it to room temperature to obtain a copper wire with copper oxide whiskers grown on its surface;

[0042] (3) Put the product obtained in the previous step into a tubular furnace and evacuate it. Then, introduce an argon / hydrogen mixed gas to atmospheric pressure and keep the tail gas overflowing. Keep it at 700 °C for 10 min for reduction treatment, and then introduce acetylene gas and keep it for 5 min. When the reaction ends, evacuate the reaction tube, naturally cool it to room temperature, and then take out the product to obtain a carbon nanotube-based flexible supercapacitor electrode. Specific embodiment eight:

[0044] (1) Take a copper wire of appropriate length, and ultrasonically clean it with dilute hydrochloric acid, acetone, and deionized water to remove surface contaminants. Place the copper wire in a vacuum oven at 60 °C and dry it for 30 min;

[0045] (2) Place the copper wire in a porcelain boat and put it into a muffle furnace at 700 °C for 1.5 h. After the reaction ends, naturally cool it to room temperature to obtain a copper wire with copper oxide whiskers grown on its surface;

[0046] (3) Put the product obtained in the previous step into a tube furnace and evacuate it. Then introduce an argon / hydrogen mixed gas to atmospheric pressure and keep the tail gas overflowing. Carry out a reduction treatment on it at 700 °C for 20 min, and then introduce acetylene gas and keep it for 10 min. After the reaction ends, evacuate the reaction tube, naturally cool it to room temperature, and then take out the product to obtain a carbon nanotube-based flexible supercapacitor electrode.

Claims

1. A preparation method of a carbon nanotube-based flexible supercapacitor electrode, characterized in that Using a copper wire as the electrode substrate and as the copper source for the air heat treatment method, copper oxide whiskers are directly prepared on its surface. Then, using the whiskers obtained by reduction heat treatment as the catalyst, the growth of carbon nanotubes on the surface of the whiskers is achieved by chemical vapor deposition. The preparation process includes the following steps: (1) Take a copper wire of appropriate length and ultrasonically clean it with dilute hydrochloric acid, acetone, and deionized water to remove surface contaminants. Place the copper wire in a vacuum oven at 60 °C and dry it for 30 min; (2) Place the copper wire in a porcelain boat and put it into a muffle furnace at 600 °C - 700 °C and hold for 1 h - 1.5 h. After the reaction ends, naturally cool it to room temperature to obtain a copper wire with copper oxide whiskers grown on its surface; (3) Put the product obtained in the previous step into a tubular furnace and evacuate it. Then, introduce an argon / hydrogen mixed gas to atmospheric pressure and hold at a temperature of 600 °C - 700 °C for 10 min - 20 min to reduce the copper oxide whiskers. Subsequently, introduce acetylene gas and hold for 5 min - 10 min. When the reaction ends, evacuate the reaction tube, naturally cool it to room temperature, and then take out the product to obtain a carbon nanotube-based flexible supercapacitor electrode.

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