Preparation method and application of three-dimensional self-supporting CuCo2O4 nano array composite current collector

Abstract

The invention relates to a preparation method and application of a three-dimensional self-supporting CuCo2O4 nano array composite current collector. According to the technical scheme, the preparation method comprises the following steps: soaking a three-dimensional self-supporting substrate material in concentrated hydrochloric acid, and carrying out ultrasonic treatment, washing and drying to obtain a pretreated three-dimensional self-supporting substrate material; the method comprises the following steps: adding copper salt into ethylene glycol according to the solution concentration of 160-200mmol / L, and stirring to obtain a solution I; adding cobalt salt and a reaction additive into the solution I according to the molar ratio of copper salt to cobalt salt to the reaction additive being 1: 2: (1-8), and stirring to obtain a solution II; and soaking the pretreated three-dimensional self-supporting substrate material in the solution II, taking out the three-dimensional self-supporting substrate material after a solvothermal reaction, soaking, washing, drying, and carrying out heat treatment to obtain the three-dimensional self-supporting CuCo2O4 nano array composite current collector. The composite current collector prepared by the invention has a layered porous structure and a high-conductivity framework, can provide abundant adsorption / catalysis sites, and can realize excellent rate capability and cycle performance when being applied to a lithium-sulfur battery.

Description

Technical Field

[0001] The present invention relates to the field of lithium-sulfur batteries, and particularly to a preparation method and application of a three-dimensional self-supporting CuCo2O4 nanoarray composite current collector. Background Art

[0002] In the context of the global energy transition, lithium-ion batteries have attracted much attention in the battery field due to their important role in reducing greenhouse gas emissions in the energy and transportation systems. However, due to the rapid development and utilization of energy storage devices, the traditional lithium-ion battery system based on the intercalation chemical reaction mechanism has been difficult to meet the urgent needs of high energy density, long cycle life, and low energy storage cost. In the process of developing new energy storage technologies, lithium-sulfur batteries based on the multi-electron conversion reaction mechanism are considered to be promising secondary batteries because of their high specific capacity (1675 mAh· g- 1), high energy density (2600 Wh·kg -1 ), low raw material price, and excellent environmental performance. However, the commercialization of lithium-sulfur batteries still faces some obstacles, such as low availability of active materials, slow redox kinetics, and serious "shuttle effect", resulting in poor Coulomb efficiency and low capacity retention rate.

[0003] A series of micro / nano sulfur carriers have been designed to overcome the above obstacles. Among them, porous carbon-based materials can physically limit the "shuttle effect" of polysulfides and improve the conversion kinetics of sulfur by accelerating electron / ion transport. However, the weak physical interaction based on van der Waals force between polysulfides and carbon-based materials is difficult to inhibit the "shuttle effect" for a long time. However, the weak physical interaction based on van der Waals force is not sufficient to inhibit the "shuttle effect". Therefore, the research focus of researchers on sulfur carriers has gradually shifted to metal oxides with enhanced chemical adsorption ability for polysulfides. However, most metal oxides have low conductivity and limited utilization rate, making it difficult to play their advantages, resulting in rapid capacity decay and low sulfur utilization rate of lithium-sulfur batteries. At the same time, the traditional two-dimensional aluminum foil current collector has a single function and is difficult to achieve a high sulfur areal loading, which limits the commercial development of lithium-sulfur batteries. The three-dimensional self-supporting substrate materials (such as carbon cloth, nickel foam, etc.) can provide rich ion / electron channels and large space structures. When used as a three-dimensional self-supporting current collector, it is expected to assemble a lithium-sulfur battery with a high sulfur areal loading. However, its own adsorption and catalytic ability for polysulfides is limited, and it is difficult to effectively inhibit the "shuttle effect" and cause obvious capacity decay. Summary of the Invention

[0004] Aiming at the problems of low conductivity and utilization rate of existing metal oxides, and the difficulty of simultaneously solving the problems of high sulfur loading and "shuttle effect" by existing two-dimensional aluminum foil current collectors, the purpose of the present invention is to provide a preparation method and application of a three-dimensional self-supporting CuCo2O4 nanoarray composite current collector. The present invention uses a simple solvothermal method to in-situ synthesize CuCo2O4 nanoarrays on a three-dimensional self-supporting substrate material. On the one hand, the highly ordered structure and large specific surface area of the CuCo2O4 nanoarrays can exhibit a large number of completely exposed, continuous, and ordered adsorption / catalytic active sites, effectively promoting the transfer of charges on the electrode surface / interface and reducing the resistance of ion transport between the electrode and the electrolyte, accelerating the redox reaction kinetics and inhibiting the "shuttle effect", and improving the utilization rate of active substances. On the other hand, the introduction of the three-dimensional self-supporting substrate material can provide rich ion / electron channels and a large spatial structure, enabling high sulfur loading and improving the structural stability of the electrode.

[0005] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0006] On the one hand, a preparation method of a three-dimensional self-supporting CuCo2O4 nanoarray composite current collector is provided, including the following steps:

[0007] 1) Immerse the three-dimensional self-supporting substrate material in concentrated hydrochloric acid, ultrasonically treat for 0.5 - 1 hour, then rinse 3 - 5 times with anhydrous ethanol and deionized water in sequence, and then dry in an oven at 60 - 80 °C for 8 - 12 hours to obtain a pretreated three-dimensional self-supporting substrate material;

[0008] 2) Add copper salt to ethylene glycol according to a solution concentration of 160 - 200 mmol / L, and stir for 0.5 - 1 hour to obtain solution I;

[0009] 3) According to the molar ratio of copper salt : cobalt salt : reaction additive of 1 : 2 : (1 - 8), add cobalt salt and reaction additive to solution I, and stir for 0.5 - 1 hour to obtain solution II;

[0010] 4) Immerse the pretreated three-dimensional self-supporting substrate material in solution II, and jointly transfer it to an autoclave for solvothermal reaction;

[0011] 5) After the reaction is completed, take out the three-dimensional self-supporting substrate material and immerse it in a mixed solution III of anhydrous ethanol and deionized water, ultrasonically treat for 0.5 - 1 hour, then rinse with deionized water, dry in an oven at 60 - 80 °C for 6 - 8 hours to remove moisture, and then place it in a tube furnace for heat treatment. After natural cooling, the three-dimensional self-supporting CuCo2O4 nanoarray composite current collector can be prepared.

[0012] The three-dimensional self-supporting substrate material is one of carbon cloth and nickel foam.

[0013] The copper salt is one of copper chloride, copper acetate, copper nitrate and copper sulfate, the cobalt salt is one of cobalt chloride, cobalt acetate, cobalt nitrate and cobalt sulfate, the reaction additive is one of urea, ammonium fluoride, and the mixture of urea and ammonium fluoride, and the molar ratio of urea to ammonium fluoride in the mixture is 3:1.

[0014] The reaction temperature of the solvothermal process is 120 - 200 °C, and the reaction time is 4 - 8 hours.

[0015] The heat treatment temperature in the tube furnace is 300 - 500 °C, the heating rate is 1 - 5 °C / minute, the heat treatment time is 3 - 6 hours, and the heat treatment atmosphere is air.

[0016] On the other hand, a preparation method of a lithium-sulfur battery based on a three-dimensional self-supporting CuCo2O4 nanoarray composite current collector is provided, including the following steps:

[0017] 1) Cut the above composite current collector to a size of 1 - 1.54 cm 2 ;

[0018] 2) Mix sulfur powder and acetylene black evenly in a mass ratio of 3:2, place them in a tube furnace, heat to 155 - 200 °C under an argon protection atmosphere and keep warm for 10 - 12 hours to obtain mixture I;

[0019] 3) Mix mixture I and polyvinylidene fluoride evenly in a mass ratio of 9:1 to obtain mixture II. According to a solution concentration of 66 - 83 mg / mL, add mixture II to N-methylpyrrolidone and stir for 2 - 4 hours to obtain solution I;

[0020] 4) Place the cut composite current collector in a suction filtration device, dropwise add 30 - 50 μL of solution I during the suction filtration process, take out the composite current collector after suction filtration is completed, and dry it in a vacuum drying oven for 10 - 12 hours to obtain the positive electrode of the lithium-sulfur battery;

[0021] 5) Assemble a lithium-sulfur battery with the positive electrode obtained above.

[0022] In summary, due to the adoption of the above technical solution, the present invention has the following positive effects compared with the prior art:

[0023] (1) The composite current collector prepared by the present invention is a CuCo2O4 nanoarray in-situ grown on a three-dimensional self-supporting substrate material. The CuCo2O4 nanoarray in this structure has a highly ordered structure and a large specific surface area, and can exhibit a large number of completely exposed, continuous, and ordered adsorption / catalytic active sites, significantly accelerating the redox reaction kinetics and inhibiting the "shuttle effect", and improving the utilization rate of active substances;

[0024] (2) Compared with traditional two-dimensional aluminum foil current collectors, the composite current collector prepared in the present invention has good flexibility and good interfacial compatibility with sulfur slurry, can provide rich ion / electron channels and a large spatial structure, significantly increase sulfur loading and inhibit the "shuttle effect" of polysulfide lithium.

[0025] (3) The sulfur composite cathode in the present invention is prepared by filtering and injecting electrode slurry into a three-dimensional composite current collector. This method can give full play to the hierarchical porous structure of the three-dimensional composite current collector and significantly improve the sulfur areal loading. Description of the Drawings

[0026] Figure 1 is the XRD pattern of the three-dimensional self-supporting carbon cloth supported CuCo₂O₄ nanosheet array composite current collector (CCO@CC) and the three-dimensional self-supporting carbon cloth (CC) current collector prepared in Example 1 of the present invention;

[0027] Figure 2 is the SEM image of the CCO@CC composite current collector prepared in Example 1 of the present invention;

[0028] Figure 3 is the cycling performance graph of the CCO@CC composite current collector and the three-dimensional self-supporting carbon cloth (CC) current collector prepared in Example 1 of the present invention for lithium-sulfur batteries;

[0029] Figure 4 is the rate performance graph of the CCO@CC composite current collector and the three-dimensional self-supporting carbon cloth (CC) current collector prepared in Example 1 of the present invention for lithium-sulfur batteries. Detailed Embodiments

[0030] The present invention will be further described below in conjunction with the drawings and specific embodiments, which is not a limitation on its protection scope. Without specific special instructions, the materials or reagents used in the present invention are common materials or reagents in the art and can be obtained from commercial products in the art.

[0031] Example 1

[0032] This example provides a preparation method of a three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector, including the following steps:

[0033] 1) Immerse the three-dimensional self-supporting carbon cloth in concentrated hydrochloric acid, ultrasonically wash for 0.5 hours, then rinse 3 times with anhydrous ethanol and deionized water in sequence, and then dry in an oven at 60 °C for 8 hours to obtain a pretreated three-dimensional self-supporting carbon cloth;

[0034] 2) Add copper acetate to ethylene glycol according to a solution concentration of 160 mmol / L and stir for 0.5 hours to obtain Solution I;

[0035] 3) Add cobalt acetate and urea to Solution I according to the molar ratio of copper acetate:cobalt acetate:urea of 1:2:1, and stir for 0.5 hours to obtain Solution II;

[0036] 4) Immerse the pretreated three-dimensional self-supporting carbon cloth in Solution II, transfer them together to an autoclave, heat to 160 °C in an oven and keep warm for 6 hours for solvothermal reaction;

[0037] 5) After the reaction is completed, take out the three-dimensional self-supporting carbon cloth and immerse it in the mixed solution III of absolute ethanol and deionized water. After ultrasonic treatment for 0.5 hours, rinse it with deionized water, dry it in an oven at 60 °C for 8 hours to remove moisture, then place it in a tube furnace and heat to 400 °C (heating rate is 1 °C / minute), keep warm for 3 hours in an air atmosphere, and after natural cooling, the three-dimensional self-supporting CuCo2O4 nanoarray composite current collector can be prepared.

[0038] The mass of the CuCo2O4 nanosheet array loaded on the three-dimensional self-supporting carbon cloth is 1.0 - 1.6 mg / cm 2 .

[0039] Based on the preparation method of the three-dimensional self-supporting CuCo2O4 nanoarray composite current collector provided in the foregoing embodiments, this embodiment provides a preparation method of a lithium-sulfur battery based on the three-dimensional self-supporting CuCo2O4 nanoarray composite current collector, including the following steps:

[0040] 1) Cut the above composite current collector to a size of 1 cm 2 ;

[0041] 2) Mix sulfur powder and acetylene black evenly according to the mass ratio of 3:2, place them in a tube furnace, and heat to 155 °C under an argon protection atmosphere and keep warm for 12 hours to obtain Mixture I;

[0042] 3) Mix Mixture I and polyvinylidene fluoride evenly according to the mass ratio of 9:1 to obtain Mixture II. According to the solution concentration of 66 mg / mL, add Mixture II to N-methylpyrrolidone and stir for 2 hours to obtain Solution I;

[0043] 4) Place the cut composite current collector in a suction filtration device, and gradually add 35 mL of Solution I dropwise during suction filtration. After suction filtration is completed, take out the composite current collector and dry it in a vacuum drying oven for 12 hours to obtain the positive electrode of the lithium-sulfur battery;

[0044] 5) Assemble a lithium-sulfur battery with the positive electrode obtained above.

[0045] The sulfur surface loading of each positive electrode of the lithium-sulfur battery is about 1.3 mg / cm 2 .

[0046] The XRD pattern and SEM image of the three-dimensional self-supporting carbon cloth-supported CuCo₂O₄ nanosheet array composite current collector (CCO@CC) prepared in this example are shown in Figure 1 and 2 respectively; the cycling performance graph and rate performance graph of the CCO@CC composite current collector prepared for assembling a lithium-sulfur battery at different charge-discharge currents are shown in Figure 3 and 4 respectively.

[0047] Example 2

[0048] This example provides a method for preparing a three-dimensional self-supporting CuCo₂O₄ nanorod array composite current collector, including the following steps:

[0049] 1) Immerse the three-dimensional self-supporting nickel foam in concentrated hydrochloric acid, ultrasonically wash for 0.5 hour, then rinse with absolute ethanol and deionized water three times in sequence, and then dry in an oven at 60 °C for 8 hours to obtain the pretreated three-dimensional self-supporting nickel foam;

[0050] 2) Add copper acetate to ethylene glycol according to a solution concentration of 160 mmol / L and stir for 0.5 hour to obtain Solution I;

[0051] 3) Add cobalt acetate and urea to Solution I according to a molar ratio of copper acetate:cobalt acetate:urea of 1:2:1 and stir for 0.5 hour to obtain Solution II;

[0052] 4) Immerse the pretreated three-dimensional self-supporting nickel foam in Solution II, transfer them together to an autoclave, heat to 160 °C in an oven and keep warm for 6 hours for a solvothermal reaction;

[0053] 5) After the reaction is completed, take out the three-dimensional self-supporting nickel foam and immerse it in the mixed solution III of absolute ethanol and deionized water, ultrasonically wash for 0.5 hour, then rinse with deionized water, dry in an oven at 60 °C for 8 hours to remove moisture, then place it in a tube furnace and heat to 400 °C (heating rate is 1 °C / minute), keep warm for 3 hours in an air atmosphere, and cool naturally to obtain the three-dimensional self-supporting CuCo₂O₄ nanorod array composite current collector.

[0054] Based on the method for preparing the three-dimensional self-supporting CuCo₂O₄ nanorod array composite current collector provided in the foregoing example, this example provides a method for preparing a lithium-sulfur battery based on the three-dimensional self-supporting CuCo₂O₄ nanorod array composite current collector, including the following steps:

[0055] 1) Cut the above composite current collector to a size of 1 cm 2 ;

[0056] 2) Mix sulfur powder and acetylene black evenly at a mass ratio of 3:2, place them in a tube furnace, heat to 155 °C under an argon protective atmosphere and keep warm for 12 hours to obtain Mixture I;

[0057] 3) Mix Mixture I and polyvinylidene fluoride evenly at a mass ratio of 9:1 to obtain Mixture II. Add Mixture II to N-methylpyrrolidone at a solution concentration of 66 mg / mL and stir for 8 hours to obtain Solution I;

[0058] 4) Place the cut composite current collector in a suction filtration device, dropwise add 35 mL of Solution I during the suction filtration process. After the suction filtration is completed, take out the composite current collector and dry it in a vacuum drying oven for 8 hours to obtain the positive electrode of the lithium-sulfur battery;

[0059] 5) Assemble a lithium-sulfur battery with the positive electrode obtained above.

[0060] Example 3

[0061] This example provides a preparation method of a three-dimensional self-supporting CuCo2O4 nanoarray composite current collector, including the following steps:

[0062] 1) Immerse the three-dimensional self-supporting carbon cloth in concentrated hydrochloric acid, ultrasonically wash for 0.5 hour, then rinse with absolute ethanol and deionized water 3 times in sequence, and then dry in an oven at 60 °C for 8 hours to obtain the pretreated three-dimensional self-supporting carbon cloth;

[0063] 2) Add copper sulfate to ethylene glycol at a solution concentration of 160 mmol / L and stir for 0.5 hour to obtain Solution I;

[0064] 3) Add cobalt sulfate and urea to Solution I according to the molar ratio of copper sulfate:cobalt sulfate:urea of 1:2:2 and stir for 0.5 hour to obtain Solution II;

[0065] 4) Immerse the pretreated three-dimensional self-supporting carbon cloth in Solution II, transfer them together to an autoclave, heat to 160 °C in an oven and keep warm for 6 hours for a solvothermal reaction;

[0066] 5) After the reaction is completed, take out the three-dimensional self-supporting carbon cloth and immerse it in a mixed solution III of absolute ethanol and deionized water, ultrasonically wash for 0.5 hour, then rinse with deionized water, dry in an oven at 60 °C for 8 hours to remove moisture, and then place it in a tube furnace and heat to 400 °C (heating rate is 1 °C / minute), keep warm for 3 hours under an air atmosphere, and cool naturally to prepare the three-dimensional self-supporting CuCo2O4 nanoarray composite current collector.

[0067] Based on the preparation method of the three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector provided in the foregoing embodiments, this embodiment provides a preparation method of a lithium-sulfur battery based on the three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector, including the following steps:

[0068] 1) Cut the above composite current collector to a size of 1 cm 2 ;

[0069] 2) Mix sulfur powder and acetylene black evenly at a mass ratio of 3:2, place them in a tubular furnace, heat to 155 °C under an argon protection atmosphere, and keep warm for 12 hours to obtain mixture Ⅰ;

[0070] 3) Mix mixture Ⅰ and polyvinylidene fluoride evenly at a mass ratio of 9:1 to obtain mixture Ⅱ. According to a solution concentration of 66 mg / mL, add mixture Ⅱ to N-methylpyrrolidone and stir for 8 hours to obtain solution Ⅰ;

[0071] 4) Place the cut composite current collector in a suction filtration device, dropwise add 35 mL of solution Ⅰ during the suction filtration process, take out the composite current collector after suction filtration is completed, and dry it in a vacuum drying oven for 8 hours to obtain the positive electrode of the lithium-sulfur battery;

[0072] 5) Assemble a lithium-sulfur battery with the positive electrode obtained above.

[0073] Example 4

[0074] This embodiment provides a preparation method of a three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector, including the following steps:

[0075] 1) Immerse the three-dimensional self-supporting carbon cloth in concentrated hydrochloric acid, ultrasonically wash for 0.5 hours, then rinse it 3 times with absolute ethanol and deionized water in sequence, and then dry it in an oven at 60 °C for 8 hours to obtain the pretreated three-dimensional self-supporting carbon cloth;

[0076] 2) According to a solution concentration of 160 mmol / L, add copper acetate to ethylene glycol and stir for 0.5 hours to obtain solution Ⅰ;

[0077] 3) According to a molar ratio of copper acetate: cobalt acetate: urea of 1:2:3, add cobalt acetate and urea to solution Ⅰ and stir for 0.5 hours to obtain solution Ⅱ;

[0078] 4) Immerse the pretreated three-dimensional self-supporting carbon cloth in solution Ⅱ, transfer them together to an autoclave, heat to 180 °C in an oven and keep warm for 6 hours for a solvothermal reaction;

[0079] 5) After the reaction is completed, take out the three-dimensional self-supporting carbon cloth and soak it in the mixed solution III of anhydrous ethanol and deionized water. After ultrasonic treatment for 0.5 hours, rinse it with deionized water, dry it in an oven at 60 °C for 8 hours to remove moisture, then place it in a tubular furnace and heat it to 400 °C (heating rate: 1 °C / minute), keep it warm in an air atmosphere for 3 hours, and after natural cooling, the three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector can be prepared.

[0080] Based on the preparation method of the three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector provided in the foregoing embodiments, this embodiment provides a preparation method of a lithium-sulfur battery based on the three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector, including the following steps:

[0081] 1) Cut the above composite current collector to a size of 1 cm 2 ;

[0082] 2) Mix sulfur powder and acetylene black evenly according to a mass ratio of 3:2, then place them in a tubular furnace, and heat them to 155 °C under an argon protection atmosphere for 12 hours to obtain mixture I;

[0083] 3) Mix mixture I and polyvinylidene fluoride evenly according to a mass ratio of 9:1 to obtain mixture II. According to a solution concentration of 66 mg / mL, add mixture II to N-methylpyrrolidone and stir for 8 hours to obtain solution I;

[0084] 4) Place the cut composite current collector in a suction filtration device, and gradually add 35 mL of solution I dropwise during the suction filtration process. After the suction filtration is completed, take out the composite current collector and dry it in a vacuum drying oven for 8 hours to obtain the positive electrode of the lithium-sulfur battery;

[0085] 5) Assemble a lithium-sulfur battery with the positive electrode obtained above.

[0086] Example 5

[0087] This embodiment provides a preparation method of a three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector, including the following steps:

[0088] 1) Immerse the three-dimensional self-supporting carbon cloth in concentrated hydrochloric acid, after ultrasonic treatment for 0.5 hours, rinse it with anhydrous ethanol and deionized water 3 times in sequence, and then dry it in an oven at 60 °C for 8 hours to obtain the pretreated three-dimensional self-supporting carbon cloth;

[0089] 2) According to a solution concentration of 160 mmol / L, add copper chloride to ethylene glycol and stir for 0.5 hours to obtain solution I;

[0090] 3) According to a molar ratio of copper chloride: cobalt chloride: urea: ammonium fluoride of 1:2:6:2, add cobalt chloride and urea to solution I and stir for 0.5 hours to obtain solution II;

[0091] 4) Immerse the pretreated three-dimensional self-supporting carbon cloth in Solution II, transfer them together to an autoclave, heat to 160 °C in an oven and keep warm for 6 hours for solvothermal reaction;

[0092] 5) After the reaction, take out the three-dimensional self-supporting carbon cloth and immerse it in the mixed solution III of absolute ethanol and deionized water. After ultrasonic treatment for 0.5 hour, rinse it with deionized water, dry it in an oven at 60 °C for 8 hours to remove moisture, then place it in a tube furnace and heat to 400 °C (heating rate is 1 °C per minute), keep warm for 3 hours in an air atmosphere, and after natural cooling, the three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector can be prepared.

[0093] Based on the preparation method of the three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector provided in the foregoing embodiments, this embodiment provides a preparation method of a lithium-sulfur battery based on the three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector, including the following steps:

[0094] 1) Cut the above composite current collector to a size of 1 cm 2 ;

[0095] 2) Mix sulfur powder and acetylene black evenly according to a mass ratio of 3:2, place them in a tube furnace, and heat to 155 °C under an argon protection atmosphere and keep warm for 12 hours to obtain Mixture I;

[0096] 3) Mix Mixture I and polyvinylidene fluoride evenly according to a mass ratio of 9:1 to obtain Mixture II. According to a solution concentration of 66 mg / mL, add Mixture II to N-methylpyrrolidone and stir for 8 hours to obtain Solution I;

[0097] 4) Place the cut composite current collector in a suction filtration device, and gradually add 35 mL of Solution I dropwise during suction filtration. After suction filtration is completed, take out the composite current collector and dry it in a vacuum drying oven for 8 hours to obtain the positive electrode of the lithium-sulfur battery;

[0098] 5) Assemble a lithium-sulfur battery with the positive electrode obtained above.

Claims

1. A preparation method of a three-dimensional self-supporting CuCo2O4 nanoarray composite current collector, characterized in that, The preparation method includes: 1) Immerse the three-dimensional self-supporting substrate material in concentrated hydrochloric acid, ultrasonically treat for 0.5 - 1 hour, then rinse with absolute ethanol and deionized water 3 - 5 times in sequence, and then dry in an oven at 60 - 80 °C for 6 - 8 hours to obtain the pretreated three-dimensional self-supporting substrate material; 2) Add copper salt to ethylene glycol according to a solution concentration of 160 - 200 mmol / L, and stir for 0.5 - 1 hour to obtain Solution I; 3) According to the molar ratio of copper salt : cobalt salt : reaction additive being 1 : 2 : (1 - 8), add cobalt salt and reaction additive to Solution I, and stir for 0.5 - 1 hour to obtain Solution II; 4) Immerse the pretreated three-dimensional self-supporting substrate material in Solution II, and jointly transfer it to an autoclave for solvothermal reaction; 5) After the reaction ends, take out the three-dimensional self-supporting substrate material and immerse it in the mixed solution III of absolute ethanol and deionized water, ultrasonically treat for 0.5 - 1 hour, then rinse with deionized water, dry in an oven at 60 - 80 °C for 8 - 12 hours to remove moisture, and then place it in a tube furnace for heat treatment. After natural cooling, the three-dimensional self-supporting CuCo₂O₄ nanoarray composite current collector can be prepared.

2. The preparation method of the three-dimensional self-supporting CuCo2O4 nanoarray composite current collector according to claim 1, characterized in that, The three-dimensional self-supporting substrate material is one of carbon cloth and nickel foam.

3. The preparation method of the three-dimensional self-supporting CuCo2O4 nanoarray composite current collector according to claim 1, characterized in that, The copper salt is one of copper chloride, copper acetate, copper nitrate, and copper sulfate, the cobalt salt is one of cobalt chloride, cobalt acetate, cobalt nitrate, and cobalt sulfate, the reaction additive is one of urea, ammonium fluoride, and the mixture of urea and ammonium fluoride, and the molar ratio of urea to ammonium fluoride in the mixture is 3 :

1.

4. The preparation method of the three-dimensional self-supporting CuCo2O4 nanoarray composite current collector according to claim 1, characterized in that, The reaction temperature of the solvothermal reaction is 120 - 200 °C, and the reaction time is 4 - 8 hours.

5. The preparation method of the three-dimensional self-supporting CuCo2O4 nanoarray composite current collector according to claim 1, characterized in that The heat treatment temperature in the tube furnace is 300 - 500 °C, the heating rate is 1 - 5 °C / minute, the heat treatment time is 2 - 4 hours, and the heat treatment atmosphere is air.

6. A method for preparing a lithium-sulfur battery using a three-dimensional self-supporting CuCo2O4 nanoarray composite current collector obtained by the method according to any one of claims 1 to 5, characterized in that, The method includes: 1) Cut the three-dimensional self-supporting CuCo2O4 nanoarray composite current collector obtained by the method according to any one of claims 1 to 5 to a size of 1 to 1.54 cm 2 ; 2) Mix sulfur powder and acetylene black evenly according to a mass ratio of 3 : 2, then place them in a tube furnace, heat to 155 - 200 °C under an argon protection atmosphere, and keep warm for 12 - 24 hours to obtain Mixture I; 3) Mix Mixture I and polyvinylidene fluoride evenly according to a mass ratio of 9 : 1 to obtain Mixture II. According to a solution concentration of 66 - 83 mg / mL, add Mixture II to N-methylpyrrolidone, and stir for 2 - 4 hours to obtain Solution I; 4) Place the cut composite current collector in a suction filtration device, and gradually add 30 - 50 μL of Solution I dropwise during the suction filtration process. After the suction filtration is completed, take out the composite current collector and dry it in a vacuum drying oven for 10 - 12 hours to obtain the positive electrode of the lithium-sulfur battery; 5) Assemble a lithium-sulfur battery with the positive electrode obtained above.

Images