A method for improving the conductivity of copper-loaded porous carbon electrodes

Abstract

This invention discloses a method for improving the conductivity of copper-loaded porous carbon electrodes. A copper source and porous carbon are mixed in water to obtain a mixture. The mixture is then subjected to hydrothermal treatment in a hydrothermal reactor, followed by centrifugation to obtain the product, which is then washed and dried to obtain copper oxide / porous carbon. The copper oxide / porous carbon is used to prepare a copper oxide / porous carbon electrode, which is then subjected to a single charge-discharge cycle in a three-electrode system to obtain a copper-loaded porous carbon electrode. This invention improves the conductivity of porous carbon by loading copper oxide onto the surface and pores of porous carbon, irreversibly converting the copper oxide into elemental copper through an electrochemical reaction. As an electrode material, no conductive agent is required, increasing the electrode's energy density. This technology is simple, easy to industrialize, and offers good economic benefits. Compared with existing technologies, the copper-loaded porous carbon prepared by this invention exhibits superior energy and power densities, making it an ideal electrode material for supercapacitors.

Description

Technical Field

[0001] This invention belongs to the field of copper-loaded porous carbon electrodes, and specifically relates to a method for improving the conductivity of copper-loaded porous carbon electrodes. Background Technology

[0002] Supercapacitors are a new type of energy storage device that falls between traditional capacitors and batteries, offering advantages such as fast charging and discharging speeds, long cycle life, and high energy density. Electrode materials are a key factor affecting the electrochemical performance of supercapacitors. Porous carbon is widely used as an electrode material in supercapacitors due to its large specific surface area, good chemical stability, and low cost. However, porous carbon electrode materials suffer from poor conductivity, which limits the improvement of supercapacitor performance.

[0003] Copper possesses excellent electrical conductivity, which can be enhanced when loaded onto porous carbon. Current techniques for reducing copper ions to elemental copper generally employ solid-state reduction, solution reduction, and electrochemical reduction methods. Solid-state reduction requires high temperatures, typically above 500℃, which can easily cause secondary damage to the electrode structure. Solution reduction requires the addition of chemical reducing agents, such as iron powder, which can affect material performance. Electrochemical reduction involves electrolyzing a solution containing copper ions, but its electrolysis efficiency is slow and it only reduces copper on the electrode surface. Therefore, there is an urgent need for a method to prepare copper-loaded porous carbon electrodes that can improve the conductivity and stability of the electrodes. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for improving the conductivity of copper-loaded porous carbon electrodes.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for improving the conductivity of a copper-loaded porous carbon electrode includes the following steps:

[0007] (1) The copper source and porous carbon are mixed in deionized water to obtain a mixed solution;

[0008] (2) The above mixture was placed in a hydrothermal reactor and subjected to hydrothermal treatment in an oven at 150℃~220℃ for 12~36 h. After the reactor was naturally cooled to room temperature, the reaction product was obtained by centrifugation. The product was then repeatedly washed with deionized water and ethanol solution and vacuum dried at 55~65℃ for 12~15 h to obtain copper oxide / porous carbon composite material.

[0009] (3) The copper oxide / porous carbon composite material is used to make a copper oxide / porous carbon electrode, and then a charge-discharge is performed in a three-electrode system to obtain a copper-loaded porous carbon electrode.

[0010] In step (1), the copper source is one or more of copper acetate, copper chloride, and copper sulfate.

[0011] In step (1), the mass ratio of the copper source to the porous carbon is 1:1 to 1:9, preferably 1:3 to 1:6. With this ratio range, the copper source can be more evenly dispersed on the surface of the porous carbon.

[0012] In step (2), the specific surface area of ​​the copper oxide / porous carbon is 800~3000 m². 2 / g.

[0013] In step (3), the preparation method of the copper oxide / porous carbon electrode is as follows: the copper oxide / porous carbon composite material is mixed evenly with the binder and then coated onto nickel foam to obtain the copper oxide / porous carbon electrode; wherein the binder is PVDF and the mass ratio of copper oxide / porous carbon composite material to PVDF is 9:1.

[0014] In step (3), the current density of a single charge and discharge cycle is 0.001A / g to 10A / g.

[0015] The application of the copper-loaded porous carbon electrode in supercapacitors involves using the copper-loaded porous carbon as the electrode material to assemble a supercapacitor.

[0016] The present invention has the following beneficial effects:

[0017] 1. This invention loads copper oxide onto the surface and pores of porous carbon, and irreversibly converts the copper oxide into elemental copper through electrochemical charge and discharge. The introduction of copper into the activated carbon electrode improves the conductivity of the electrode, reduces the internal resistance of the electrode, and is beneficial to improving the charge and discharge efficiency of the supercapacitor.

[0018] 2. When the copper oxide / porous carbon electrode of the present invention is used as an electrode material, there is no need to use a conductive agent, thereby improving the energy density of the electrode.

[0019] 3. The preparation method of copper-loaded porous carbon electrodes is simple, low in cost, and easy to realize industrial production.

[0020] 4. Compared with the prior art, the copper-loaded porous carbon prepared by this invention has excellent energy density and power density, making it an ideal electrode material for supercapacitors. Attached Figure Description

[0021] Figure 1 This is a scanning electron microscope image of the copper oxide / porous carbon prepared in Example 1.

[0022] Figure 2 The cyclic voltammetry curves of the copper-loaded porous carbon prepared in Example 1 at different scan rates are shown. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the scope of protection of the present invention is not limited to these embodiments.

[0024] All technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Example 1

[0025] A method for improving the conductivity of a copper-loaded porous carbon electrode includes the following steps:

[0026] (1) Weigh copper acetate and porous carbon at a mass ratio of 1:5. First, dissolve copper acetate in 50 mL of deionized water, then add porous carbon and shake in a shaker for 1 h to obtain a mixture.

[0027] (2) The above mixture was transferred to a hydrothermal reactor and hydrothermally treated in an oven at 180°C for 24 h. After the reactor cooled to room temperature, the reaction product was obtained by centrifugation. Then, the product was repeatedly washed with deionized water and ethanol solution and vacuum dried at 60°C for 12 h to obtain copper oxide / porous carbon composite material.

[0028] (3) The copper oxide / porous carbon composite material and the binder PVDF are mixed evenly at a mass ratio of 9:1, and then coated onto the nickel foam to obtain the copper oxide / porous carbon electrode.

[0029] (4) The obtained copper oxide / porous carbon electrode is charged and discharged once in a three-electrode system with a charge and discharge current density of 0.5 A / g to obtain a copper-loaded porous carbon electrode.

[0030] The copper oxide / porous carbon prepared in this embodiment has a specific surface area of ​​2500 m². 2 / g. The prepared copper-loaded porous carbon electrode was assembled onto a supercapacitor, and a specific capacitance of 500 F / g was obtained at a current density of 0.5 A / g, and a specific capacitance of 280 F / g was obtained at a high current density of 10 A / g. The capacitance retention rate was 92% after 10,000 cycles.

[0031] Figure 2The figures show the cyclic voltammetry curves of the copper-loaded porous carbon prepared in Example 1 at different scan rates. It can be seen that the cyclic voltammetry curve area is smallest at a scan rate of 5 mV / s. As the scan rate increases, the integral area of ​​the cyclic voltammetry curve expands, and the redox peaks on the curve gradually become less prominent. This is because at lower scan rates, electrolyte ions can diffuse more fully, resulting in more effective surface areas for Faraday redox reactions. With increasing scan rate, the diffusion time of electrolyte ions to the reactive sites inside the electrode is limited, leading to incomplete Faraday redox reactions. When the scan rate reaches 200 mV / s, the curve is close to a rectangular shape, exhibiting good capacitance characteristics. Furthermore, due to the weak polarization of the electrode, the positions of the redox peaks change slightly, indicating that the prepared composite material has good reversible charge-discharge capability. Example 2

[0032] A method for improving the conductivity of a copper-loaded porous carbon electrode includes the following steps:

[0033] (1) Weigh copper acetate and porous carbon at a mass ratio of 1:8. First, dissolve copper acetate in 50 mL of deionized water, then add porous carbon and shake in a shaker for 1 h to obtain a mixture.

[0034] (2) The mixture was transferred to a hydrothermal reactor and hydrothermally treated in an oven at 22 °C for 24 h. After the reactor cooled to room temperature, the reaction product was obtained by centrifugation. The product was then repeatedly washed with deionized water and ethanol solution and vacuum dried at 60 °C for 12 h to obtain copper oxide / porous carbon composite material.

[0035] (3) The copper oxide / porous carbon composite material and the binder PVDF are mixed evenly at a mass ratio of 9:1, and then coated onto the nickel foam to obtain the copper oxide / porous carbon electrode.

[0036] (4) The obtained copper oxide / porous carbon electrode is charged and discharged once in a three-electrode system with a charge and discharge current density of 0.5 A / g to obtain a copper-loaded porous carbon electrode.

[0037] The copper oxide / porous carbon prepared in this embodiment has a specific surface area of ​​1500 m². 2 / g. The prepared copper-loaded porous carbon electrode was assembled onto a supercapacitor, and a specific capacitance of 350 F / g was obtained at a current density of 0.5 A / g, and a specific capacitance of 160 F / g was obtained at a high current density of 10 A / g. The capacitance retention rate was 91% after 10,000 cycles. Example 3

[0038] A method for preparing a copper-loaded porous carbon electrode to improve conductivity includes the following steps:

[0039] (1) Weigh copper acetate and porous carbon at a mass ratio of 1:2. First, dissolve copper acetate in 50 mL of deionized water, then add porous carbon and shake in a shaker for 1 h to obtain a mixture.

[0040] (2) The mixture was transferred to a hydrothermal reactor and hydrothermally treated in an oven at 190°C for 24 h. After the reactor cooled to room temperature, the reaction product was obtained by centrifugation. The product was then repeatedly washed with deionized water and ethanol solution and vacuum dried at 60°C for 12 h to obtain copper oxide / porous carbon composite material.

[0041] (3) The copper oxide / porous carbon composite material and the binder PVDF are mixed evenly at a mass ratio of 9:1, and then coated onto the nickel foam to obtain the copper oxide / porous carbon electrode.

[0042] (4) The obtained copper oxide / porous carbon electrode is charged and discharged once in a three-electrode system with a charge and discharge current density of 0.5 A / g to obtain a copper-loaded porous carbon electrode.

[0043] The copper oxide / porous carbon prepared in this embodiment has a specific surface area of ​​800 m². 2 / g. The prepared copper-loaded porous carbon electrode was assembled onto a supercapacitor, and a specific capacitance of 250 F / g was obtained at a current density of 0.5 A / g, and a specific capacitance of 130 F / g was obtained at a high current density of 10 A / g. The capacitance retention rate was 95% after 10,000 cycles.

Claims

1. A method for improving the conductivity of a copper-loaded porous carbon electrode, characterized in that, Includes the following steps: (1) A copper source and porous carbon are mixed in water to obtain a mixture, wherein the copper source is one or more of copper acetate, copper chloride, and copper sulfate; (2) The above mixture is placed in a hydrothermal reactor and subjected to hydrothermal treatment in an oven at 150℃~220℃ for 12~36 h. After the reactor is cooled to room temperature, the reaction product is obtained by centrifugation. The product is then washed and dried to obtain copper oxide / porous carbon composite material. (3) The copper oxide / porous carbon composite material is used to make a copper oxide / porous carbon electrode, and then a charge-discharge is performed in a three-electrode system to obtain a copper-loaded porous carbon electrode.

2. The method for improving the conductivity of a copper-loaded porous carbon electrode according to claim 1, characterized in that, In step (1), the mass ratio of the copper source to the porous carbon is 1:1 to 1:

9.

3. The method for improving the conductivity of a copper-loaded porous carbon electrode according to claim 1, characterized in that, The specific surface area of ​​the copper oxide / porous carbon is 800~3000 m². 2 / g.

4. The method for improving the conductivity of a copper-loaded porous carbon electrode according to claim 1, characterized in that, In step (3), the copper oxide / porous carbon electrode is prepared by mixing the copper oxide / porous carbon composite material with a binder and then coating it onto nickel foam to obtain the copper oxide / porous carbon electrode.

5. The method for improving the conductivity of a copper-loaded porous carbon electrode according to claim 4, characterized in that, The binder is PVDF, and the mass ratio of copper oxide / porous carbon composite material to PVDF is 9:

1.

6. The method for improving the conductivity of a copper-loaded porous carbon electrode according to claim 1, characterized in that, In step (3), the current density of a single charge and discharge cycle is 0.001A / g to 10A / g.

7. A copper-loaded porous carbon electrode is obtained by the method according to any one of claims 1 to 6.

8. The application of the copper-loaded porous carbon electrode as described in claim 7 in a supercapacitor.

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