Preparation method of copper oxide / carbon composite electrode material

Abstract

The invention discloses a preparation method of a copper oxide / carbon composite electrode material, and belongs to the technical field of preparation and application of electrochemical electrode materials. The preparation method comprises the following steps: preparing cellulose aerogel from cotton powder through an ionic liquid sol-gel process, loading the cellulose aerogel with copper salt, and carbonizing to obtain the copper oxide / carbon composite electrode material. The material has the advantages of large specific surface area, uniform copper oxide distribution, and high mass specific capacitance and energy density.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical electrode material preparation and application technology, specifically relating to a method for preparing a copper oxide / carbon composite electrode material. Background Technology

[0002] A supercapacitor is an electronic component that can quickly store and release energy. It has a high power density and can provide a faster charge and discharge rate than a battery. However, the low energy density of supercapacitors limits their widespread application.

[0003] Electrode materials directly affect the electrochemical performance of supercapacitors. Based on the principle of capacitance generation, the electrode materials used in supercapacitors can be divided into double-layer electrode materials and pseudocapacitive electrode materials.

[0004] Carbon materials such as activated carbon, graphene, carbon nanotubes, and carbon aerogels, when used as double-layer electrode materials, generally possess a large specific surface area and exhibit good electrochemical performance. Liu et al. prepared porous carbon aerogels using nanocellulose as a raw material, assembled them with reduced graphene oxide, and fabricated a solid-state supercapacitor using PVA / H₂SO₄ as the gel electrolyte, achieving a performance of 3 mA·cm⁻¹. -2 The capacitance retention rate can be maintained at 82% after 5000 cycles at current density (Liu HY, Xu T, Liang QD, et al. Compressible cellulose nanofibrils / reduced graphene oxide compositecarbon aerogel for solid-state supercapacitor[J]. Advanced Composites and Hybrid Materials, 2022, 5(2): 1168-1179.).

[0005] Metal oxides are commonly used pseudocapacitive electrode materials. To further improve the energy density of electrode materials, carbon materials and pseudocapacitive electrode materials can be composited using different methods. Zhang et al. prepared CuO microspheres adsorbed with glucose, followed by calcination, to prepare a composite electrode material of CuO and graphene, with a specific surface area and specific capacitance reaching 106.6 m². 2 ·g -1 and 677 F·g -1(Zhang J, Zhang GF, Luo WH, et al. Graphiticcarbon coated CuO hollow nanospheres with penetrated mesochannels for high-performance asymmetric supercapacitors[J]. ACS Sustainable Chemistry & Engineering, 2017, 5(1): 105-111.). Dong et al. prepared carbon aerogels using phloroglucinol-resorcinol-formaldehyde gel as precursors, and then prepared composite electrode materials by adsorbing copper nitrate. The specific surface area and specific capacitance were 450 m² / m³. 2 ·g -1 and 255 F·g -1 (Dong XX, Xu YL, Wang SS, et al. A comparison of electrochemical performance of carbon aerogels with adsorption metal ions for super capacitors[J]. Materials, 2018, 11(11): 2271.).

[0006] Studies have shown that carbon aerogels possess a large specific surface area, making them an excellent substrate for preparing electrode materials. The composite process of copper oxides, as pseudocapacitive materials, with carbon materials has also been investigated, demonstrating promising application prospects. For copper oxide / carbon composite electrode materials, a large specific surface area and good copper oxide dispersion are crucial for improving the performance of the electrode materials. Summary of the Invention

[0007] To prepare copper oxide / carbon composite electrode materials with large specific surface area and good copper oxide dispersion, the following preparation method is proposed, including the following steps: (1) Mix cotton powder and 1-allyl-3-methylimidazolium chloride ionic liquid, wherein the mass fraction of cotton powder is 1-3%, heat the mixture in a flask to make it into a solution, the heating temperature is 120°C, and then pour it into a container to obtain cellulose gel. (2) Place the cellulose gel in an aqueous solution of tert-butanol for ≥8 hours. The concentration of tert-butanol in the aqueous solution is 50%-100%. Then freeze it in liquid nitrogen for 10 minutes and then freeze-dry it in a vacuum for 24 hours to obtain cellulose aerogel. (3) The cellulose aerogel is placed in an ethanol-water solution with a volume ratio of ethanol to water of 1:1. The amount of ethanol-water solution is 100 times the mass of the cellulose aerogel. Copper acetate, copper sulfate or copper nitrate are added with a mass of 10%-30% of the mass of the cellulose aerogel. Copper oxide / carbon composite electrode material is obtained by rotary evaporation and carbonization in a tube furnace. The carbonization conditions are argon atmosphere and temperature of 700-900℃.

[0008] This method results in a large specific surface area of ​​carbon aerogel substrate, uniform copper salt loading, and a long discharge time, leading to copper oxide / carbon aerogel materials with a large specific surface area and high specific capacitance. Attached Figure Description

[0009] The accompanying drawings described herein are provided to further illustrate this application and form part of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute a limitation thereof. Figure 1 The constant current charge-discharge curves of the samples prepared in Examples 1, 2 and 3 at a current density of 2A / g are shown. Detailed Implementation

[0010] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all of them. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present application can be combined with each other. Example 1

[0011] A method for preparing a copper oxide / carbon composite electrode material includes the following steps: (1) Weigh 0.20 g of cotton cellulose and 19.60 g of ionic liquid into a three-necked flask, stir for 2 h in an oil bath at 120 ℃, and pour into a weighing bottle while hot to obtain cellulose gel. (2) Place the cellulose gel in a 50% tert-butanol aqueous solution, remove it after 8 hours and freeze it in liquid nitrogen for 10 minutes, then freeze-dry it under vacuum for 24 hours to obtain cellulose aerogel. (3) Crush 1 g of cellulose aerogel and place it in 100 g of ethanol aqueous solution with a volume ratio of ethanol to water of 1:1. Add 0.1 g of copper acetate and stir evenly. After rotary evaporation, place it in a tube furnace under an argon atmosphere for carbonization at a carbonization temperature of 700 ℃ to obtain copper oxide / carbon electrode material.

[0012] The specific surface area of ​​the material is 265 m².2 ·g -1 In the three-electrode constant current charge-discharge detection, the current density is 2 A·g -1 At that time, the specific capacitance reached 239 F·g -1 . Example 2

[0013] A method for preparing a copper oxide / carbon composite electrode material includes the following steps: (1) Weigh 0.40 g of cotton cellulose and 19.60 g of ionic liquid into a three-necked flask, stir for 2 h in an oil bath at 120 ℃, and pour into a weighing bottle while hot to obtain cellulose gel. (2) Place the cellulose gel in 100% tert-butanol, take it out after 24 hours, freeze it in liquid nitrogen for 10 minutes, and freeze-dry it under vacuum for 24 hours to obtain cellulose aerogel. (3) Crush 1 g of cellulose aerogel and put it into 100 g of ethanol-water solution with a volume ratio of ethanol to water of 1:1. Add 0.20 g of copper nitrate and stir evenly. After rotary evaporation, place it in a tube furnace under an argon atmosphere for carbonization. The carbonization temperature is set to 850 ℃. After carbonization, copper oxide / carbon electrode material is obtained.

[0014] The specific surface area of ​​the material is 311 m². 2 ·g -1 In the three-electrode constant current charge-discharge detection, the current density is 2 A·g -1 At that time, the specific capacitance reached 294 F·g -1 . Example 3

[0015] A method for preparing a copper oxide / carbon composite electrode material includes the following steps: (1) Weigh 0.60 g of cotton cellulose and 19.60 g of ionic liquid into a three-necked flask, stir for 2 h in an oil bath at 120 ℃, and pour into a weighing bottle while hot to obtain cellulose gel. (2) Place the cellulose gel in 100% tert-butanol, take it out after 24 hours, freeze it in liquid nitrogen for 10 minutes, and freeze-dry it under vacuum for 24 hours to obtain cellulose aerogel. (3) Crush 1 g of cellulose aerogel and put it into 100 g of ethanol-water solution with a volume ratio of ethanol to water of 1:1. Add 0.28 g of copper sulfate and stir evenly. After rotary evaporation, place it in a tube furnace under an argon atmosphere for carbonization. The carbonization temperature is set to 850 ℃. After carbonization, copper oxide / carbon electrode material is obtained.

[0016] The specific surface area of ​​the material is 374 m². 2 ·g -1 In the three-electrode constant current charge-discharge detection, the current density is 2 A·g -1 At that time, the specific capacitance reached 932 F·g -1 .

Claims

1. A method for preparing a copper oxide / carbon composite electrode material, characterized by, The method comprises the following steps: (1) mixing cotton powder and 1-allyl-3-methylimidazolium chloride ionic liquid, heating to form a solution in a flask at 120℃, and then pouring into a container to obtain a cellulose gel; (2) placing the cellulose gel prepared in step (1) in a tert-butyl alcohol solution for ≥6 hours, freezing in liquid nitrogen for 10 min, and then vacuum freeze-drying for 24 h to obtain a cellulose aerogel; (3) placing the cellulose aerogel obtained in step (2) into an ethanol-water solution (volume ratio 1:1) with a mass of 100 times, adding a copper salt, and then performing rotary evaporation and tube furnace carbonization to obtain a copper oxide / carbon composite electrode material.

2. The method for preparing a copper oxide / carbon composite electrode material according to claim 1, characterized in that, In step (1), the cotton powder and the 1-allyl-3-methylimidazolium chloride ionic liquid are mixed, and the mass ratio of the cotton powder is 1-3%.

3. The method of claim 1, wherein the copper oxide / carbon composite electrode material is prepared by the steps of: mixing copper oxide and carbon black to form a mixture; and heating the mixture to form the copper oxide / carbon composite electrode material. In step (2), the concentration of the tert-butyl alcohol solution is 50%-100%.

4. The method of claim 1, wherein the copper oxide / carbon composite electrode material is prepared by the steps of: mixing copper oxide and carbon black; and mixing the mixture with a binder. In step (3), the copper salt added is copper acetate, copper nitrate or copper sulfate, and the mass is 10%-50% of the mass of the cellulose aerogel.

5. The method of claim 1, wherein the copper oxide / carbon composite electrode material is prepared by the steps of: mixing copper oxide and carbon black; and mixing the mixture with a binder. In step (3), the tube furnace carbonization condition is an argon atmosphere, and the carbonization temperature is 700-900℃.

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