A copper-nickel sulfide electrode material, its preparation, method for coating with a porous material, and application

Abstract

The present invention relates to a copper-nickel sulfide electrode material, its preparation, a porous material coating method and applications, and includes the following steps: using three different metal sheets as conductive substrates and metal sources, thiourea or thioacetamide as sulfur sources, a mixed solution of deionized water and absolute ethanol or pure deionized water as the solution, and synthesizing a copper-supported copper-nickel sulfide electrode material by a simple one-pot method; further coating the copper-supported copper-nickel sulfide with porous materials such as filter paper and diaphragm to construct a coated electrode, which can effectively prevent the active material from falling off into the solution due to structural changes during cycling. During the electrochemical reaction process, part of the copper-nickel sulfide is deposited on the porous material, which can significantly increase the specific surface area of the active material and significantly improve its capacity, and has ultra-high cycle stability. The prepared electrode material has a very high capacity and surprisingly ultra-high cycle stability, and can be applied to next-generation high-performance energy storage devices such as supercapacitors, lithium batteries, and lithium-sulfur batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of synthesis of new energy storage materials and nanomaterials, and particularly relates to a copper sheet-supported nano copper-nickel sulfide electrode material, a preparation method thereof, a method for coating the porous material, and an application in energy storage devices such as supercapacitors. Background Art

[0002] With the growth of the global population and the continuous improvement of people's living standards, the consumption of fossil fuels such as coal and oil has been increasing continuously. The emission of a large amount of greenhouse gases has caused global warming and the melting of polar glaciers, resulting in frequent extreme weather such as global typhoons, heavy rains and droughts, as well as regional wildfires and insect disasters, which seriously threaten human survival. Therefore, controlling the emission of greenhouse gases such as carbon dioxide has become a major issue faced by all mankind. Replacing fossil fuels with renewable energy sources such as solar energy, wind energy and tidal energy is an effective way to reduce carbon emissions. However, their three characteristics (randomness, volatility and intermittency) will bring fluctuations to the power grid. The application of reasonable energy storage technology can ensure the stable operation of the power system, improve its reliability and safety. Therefore, energy storage technology is the key to the development of new energy. In recent years, electric vehicles and energy storage rail vehicles vigorously developed by various countries are gradually replacing fuel vehicles, which also brings new development opportunities to new energy storage technologies with high energy density and high power density.

[0003] Supercapacitors, as a new type of energy storage device, have the advantages of high power density, fast charging speed, long service life, safety, environmental protection and good low-temperature performance, and are widely used in fields such as electric vehicles, buses, rail transit braking energy recovery systems and port cranes. At present, the energy density of the electric double layer supercapacitor based on activated carbon is relatively low (5-10 Wh kg -1 ), which is much lower than that of widely used lithium batteries (100-300 Wh kg -1 ). Therefore, it cannot meet the needs of various industries for supercapacitors with high energy density. According to the energy density formula E = 1 / 2CV 2 , improving the capacity of the electrode material and assembling an asymmetric supercapacitor with a wide potential window from positive and negative electrode materials with opposite potentials are two effective ways to improve the energy density of the device. Transition metal compounds have become the focus and key point of supercapacitor research due to the Faraday pseudocapacitance reaction with higher theoretical capacity. After years of efforts by scientific researchers, the capacity of the positive electrode material of supercapacitors has reached as high as 2000-3500 F g -1 , while the negative electrode material has stagnated. The capacity of the reported negative electrode materials is generally lower than 1000 F g -1, far lower than that of the positive electrode material, which causes a serious mismatch between the positive and negative electrodes of the supercapacitor, namely the so-called "barrel effect", greatly restricting the improvement of the energy density of the supercapacitor. More importantly, when the pseudocapacitive electrode material undergoes a Faraday reaction, it will fall off due to the volume and structural changes of the material, resulting in poor cycle stability, thus restricting the wide application of supercapacitors in actual production. Therefore, designing and developing supercapacitor negative electrode materials with high capacity and excellent cycle stability is a huge challenge at present.

[0004] At present, the research on supercapacitor negative electrode materials mainly focuses on transition metal oxides / sulfides and their composites such as iron, molybdenum, vanadium, and copper. For example, the Fe2O3@VN core-shell structure negative electrode material has an areal specific capacitance and a mass specific capacitance of 0.32 F cm -2 and 265.4 F g -2 respectively at a current density of 5 mA cm -1 (Hao Zhou, et al. Synergy of VN and Fe2O3 Enables High Performance Anodes for Asymmetric Supercapacitors[J]. ACS Appl. Mater. Interfaces 2023, 15: 18819-18827). Wang et al. prepared the MoS2 / NiS composite negative electrode material on nickel foam by electrodeposition and ion layer adsorption reaction methods. The electrolyte was 1.0 M aqueous Na2SO4 solution, and the areal specific capacitance was 0.72 F cm -2 at a current density of 1 mA cm -2 (Hongyan Wang, et al. In situ growth MoS2 / NiS composites on Ni foam as electrode materials for supercapacitors[J]. Materials Today Communications, 2023, 34: 105041). It can be seen that iron, molybdenum, and vanadium oxides / sulfides and their composites as supercapacitor negative electrode materials have very low capacities and are difficult to meet the requirements of high-performance supercapacitors. In recent years, layered transition metal sulfides have become a new type of energy storage electrode material. Copper sulfide, as an important transition metal chalcogenide, is a typical p-type semiconductor. Copper sources have good electrochemical properties due to their characteristics of rich reserves, low price, variable valence states, and abundant redox reaction sites on the earth, and are widely used in fields such as lithium-ion batteries, supercapacitors, and catalysts. For example, Han et al. prepared the Cu7S4 negative electrode material by the hard template method, and at a current density of 1 A g -1The specific capacitance at [specific condition] is about 390 F g -1 , and the capacitance retention rate at 10 A g -1 is 53.7%. For the Ta-Cu7S4 negative electrode material synthesized by Ta doping, the specific capacitance at 1 A g -1 is increased to 675 F g -1 , and the capacitance retention rate at 10 A g -1 is 53.8%. The prepared electrode material does not provide stable cycling performance (Xuzhao Han, et al. Construction of Ta-Cu7S4 negative electrode for high-performance all-solid-state asymmetric supercapacitor[J]. Chemical Engineering Journal, 2021, 403:126471). The heterostructured CuS / Fe2O3 electrode material prepared by Han et al. using the precipitation method combined with calcination and selective sulfidation has a negative electrode performance of 921 F g -1 at 1 A g -1 , and the prepared electrode material also does not provide stable cycling performance (Xuzhao Han, et al. Construction of vacancies-enriched CuS / Fe2O3 with nano-heterojunctions as negative electrode for flexible solid-state supercapacitor[J]. Journal of Alloys and Compounds, 2022, 916:165443). Zhang et al. in-situ prepared the Cu(OH)2 / CF nanowire negative electrode material on copper foam by the room-temperature oxidation method. According to the discharge time calculation, the areal specific capacitance at a current density of 5 mA cm -2 is 1.6 F cm -2; Then, the Fe3O4 / CuO / CF negative electrode material was synthesized by an electrodeposition combined with calcination process. After 4 cycles, the capacity decreased to 20% of the initial value, and after 2000 cycles, the specific capacitance decreased to about 3.5%. After 4500 cycles, it was 3%. Further, through a carbon coating process, the Fe3O4@C / CuO / CF nanotube negative electrode material was synthesized, and the capacitance retention rate after 5000 cycles was increased to 88% (Dongbin Zhang, et al. Hierarchical carbon-decorated Fe3O4 on hollow CuO nanotube array: Fabrication and used as negative material for ultrahigh-energy density hybrid supercapacitor[J]. Chemical Engineering Journal, 2018, 349: 491-499). Nickel sulfide has the advantages of being relatively easy to manufacture, relatively friendly to the environment and humans, and having a high capacity, and is considered a promising electrode material for supercapacitors. For example, Wang et al. prepared a nickel foam-supported nano-MoS2 / NiS composite negative electrode material by an electrodeposition method and an ion layer adsorption reaction method. The electrolyte was an aqueous solution of 1.0 M Na2SO4, and the test potential window was -1.0 to -0.3 V. The areal specific capacitance at 1 mA cm -2 was 0.72 F cm -2 (Hongyan Wang, et al. In situ growth MoS2 / NiS composites on Ni foam as electrode materials for supercapacitors[J]. Materials Today Communications, 2023, 34: 105041). It can be seen that as negative electrode materials for supercapacitors, the relatively wide band gaps of nano-copper hydroxide and copper sulfide hinder the movement of carriers to the conduction band, resulting in a decrease in the electrical conductivity of the materials and poor electrochemical performances such as capacity and cycle stability; NiS can be compounded with other sulfides as a negative electrode material, but its capacity is low.

[0005] In order to solve the electrochemical performance problems of copper sulfide-based anode materials, such as complex preparation process, low conductivity, low capacity and poor cycle stability, based on the existence of a special synergistic effect between two active substances in the composite material, as well as the formed heterojunction and the generated internal electric field, which change the internal electronic structure of the material. During the charge and discharge process, the transfer rate of electrons can be effectively increased, thereby improving the conductivity and capacity of the material. Therefore, by compounding copper sulfide with other metal sulfides to obtain copper sulfide-based compounds, it is expected to improve the capacitance performance of the electrode material. More importantly, in order to eliminate the problem that the structural change of the electrode material during the electrochemical reaction causes it to fall off into the solution, resulting in a significant decrease in cycle stability, the electrode is coated with a porous material, which can not only protect the electrode, but also prevent the active material from falling off into the solution, and does not affect the transfer of electrolyte ions, thereby significantly improving its cycle stability. Based on the above ideas, we designed a high-capacity copper nickel sulfide electrode material with a heterojunction synthesized by a simple one-pot method using three different metal sheets as metal sources and conductive substrates; further, a coated electrode was prepared by simply coating the electrode material with porous materials such as filter paper, separator and nickel foam, which can effectively prevent the active material from falling off during the electrochemical reaction, thereby significantly improving its capacity and cycle stability. This method has important theoretical research and industrial large-scale production application value. Summary of the Invention

[0006] Aiming at the deficiencies of the existing copper-based sulfide electrode materials, such as low capacity, poor cycle stability and complex preparation process, the purpose of the present invention is to provide a copper nickel sulfide electrode material, its preparation, a coating method with porous materials and its application. The prepared electrode material has a high specific capacitance per unit area; further, it is coated and protected with a porous material to prevent the active material from falling off into the solution during the cycle, and has excellent cycle stability, and is expected to be widely used in high-performance supercapacitors, lithium batteries and other energy storage devices.

[0007] In order to achieve the purpose of the present invention, the technical solution of the present invention is a copper nickel sulfide electrode material, its preparation and a coating method for improving cycle stability, including the following preparation steps:

[0008] (1) Ultrasonically pickling a certain area of nickel foam or nickel mesh, copper foam or copper mesh, and copper sheet in 3M HCl solution for 10-15 minutes, then ultrasonically cleaning in deionized water 3-5 times until the solution is neutral, and cleaning and drying in absolute ethanol.

[0009] (2) Dissolve thiourea or thioacetamide in the solution, and obtain a uniform mixed solution after magnetic stirring.

[0010] (3) Transfer the mixed solution into a polytetrafluoroethylene inner liner, add three different pre-treated metal sheets, seal the reaction kettle, and carry out a heating reaction in a forced-air drying oven; after the reaction, cool to room temperature, and obtain copper sheets loaded with nano copper-nickel sulfide after washing and drying.

[0011] (4) Take the copper sheets loaded with copper-nickel sulfide with a size of 1.0 cm × 1.0 cm, coat them with a porous material, and construct a coated electrode with high cycle stability.

[0012] In step 1, the areas of the nickel foam or nickel mesh and the copper foam or copper mesh are 0.25 to 0.5 times and 0.25 to 1 times the area of the copper sheet, respectively.

[0013] In step 2, the concentration of thiourea or thioacetamide in the mixed solution is 30 to 50 mM.

[0014] In step 2, the solution is a mixed solution of deionized water and absolute ethanol with a volume ratio of 1:3 or pure deionized water.

[0015] In step 3, the reaction temperature is 90 to 160 °C, and the reaction time is 1 to 10 h.

[0016] In step 4, the porous material is filter paper or diaphragm or nickel foam.

[0017] In step 4, the area of the porous material ≥ the area of the copper substrate.

[0018] In step 4, the coating method is that the filter paper or diaphragm coats the two side faces and the bottom face of the copper sheet in a U shape, and the nickel foam coats the two side faces of the copper sheet in a sandwich shape.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) The present invention uses nickel foam, copper foam and copper sheets to provide nickel source and copper source respectively, regulates their different area ratios with the copper sheet, uses thiourea or thioacetamide as the sulfur source, and a mixed solution of absolute ethanol and deionized water or pure deionized water as the solvent, and synthesizes a copper sheet loaded with nano copper-nickel sulfide electrode material through a solvothermal or hydrothermal reaction. The active material grows firmly in-situ on the conductive copper sheet, having good mechanical stability and conductivity, and avoiding the use of metal salts, binders and complex coating processes.

[0021] (2) In the present invention, under the etching of thiourea, in addition to the copper sheet itself generating Cu 2+ in addition, the nickel foam and copper foam have a large specific surface area, and a large amount of Cu 2+ and Ni 2+ enter the solution and diffuse to the vicinity of the copper sheet, combine with sulfide ions, and generate a composite of copper sheet loaded with nano copper-nickel sulfide composed of copper sulfide and a small amount of nickel sulfide.

[0022] (3) In the copper-nickel sulfide composite of the present invention, the introduction of nickel sulfide causes the synergistic effect of multiple components, the formation of nanoheterojunctions and the generated internal electric field, and can provide more electroactive sites, which can significantly improve the fast electron transfer kinetics of the electrode material, thereby enhancing its conductivity and capacity.

[0023] (4) The copper sheet supported nano copper-nickel sulfide of the present invention has excellent supercapacitor negative electrode performance. At a relatively high current density of 10 mA cm -2 , the highest areal specific capacitance reaches 12.06 F cm -2 , and it can be applied to fields such as high-performance supercapacitors, lithium-ion batteries, and electrocatalysis. The preparation process of this composite electrode material is simple, does not require metal salts, does not use complex equipment and devices, is green and environmentally friendly, and is convenient for large-scale industrial production.

[0024] (5) The coated electrode constructed by coating the copper sheet supported copper-nickel sulfide with porous materials such as filter paper, separator, or nickel foam can, on the one hand, effectively prevent the active material from falling off into the solution due to structural changes during the cycling test, and on the other hand, during the electrochemical reaction process, part of the copper-nickel sulfide can be deposited on these porous materials, further increasing the specific surface area of the active material and fully participating in the pseudocapacitance reaction, greatly improving its utilization rate. The capacity of this electrode material continuously increases during the charge-discharge cycling process at a very high current density of 100 mA cm -2 . After 750 cycles, its capacity reaches an astonishing 117.27 F cm -2 , which is 1906% of the initial capacitance value, showing excellent cycle stability. The preparation process of coating the electrode with porous materials is a simple, convenient, and efficient method to improve its capacity and cycle stability, and it can not only be applied to the next generation of high-performance supercapacitors, but also is expected to be widely used in high-energy storage devices such as lithium batteries and lithium-sulfur batteries. Brief Description of the Drawings

[0025] Figure 1 Fig. is the cyclic voltammetry curves of the copper sheet supported nano copper-nickel sulfide electrode material prepared in Example 1 at different scanning rates.

[0026] Figure 2 Fig. is the galvanostatic charge-discharge curves of the copper sheet supported nano copper-nickel sulfide electrode material prepared in Example 1 at current densities of 5 and 10 mA cm -2 .

[0027] Figure 3 Fig. is the galvanostatic charge-discharge curves of the copper sheet supported nano copper-nickel sulfide electrode materials prepared in Examples 2 to 5 at a current density of 10 mA cm -2 .

[0028] Figure 4For Example 5, the copper sheet-supported nano copper-nickel sulfide electrode material prepared with thioacetamide as the sulfur source at different reaction times has a constant current charge-discharge curve at a current density of 5 mA cm -2 when.

[0029] Figure 5 For the porous material-coated copper sheet-supported nano copper-nickel sulfide electrode material in the example, the cyclic stability curve at a current density of 100 mA cm -2 for 750 cycles.

[0030] Figure 6 For the porous material-coated copper sheet-supported nano copper-nickel sulfide electrode material in the example, the constant current charge-discharge curves at the 1st and 750th cycles at a current density of 100 mA cm -2 . Detailed implementation mode

[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further elaborated in detail below with reference to examples and drawings. It should be understood that the examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0032] Example 1

[0033] (1) Take a copper sheet with a size of 2.2 cm × 6.0 cm 2 , nickel foam of 2.0 × 2.2 cm 2 and copper foam of 2.0 × 2.2 cm 2 , ultrasonically clean in 3M HCl solution for 15 min to remove surface oxides and impurities, then ultrasonically clean in deionized water 3 - 5 times until the solution is neutral, soak in absolute ethanol, and dry in a blast drying oven at 60 °C for 60 min to obtain 3 pretreated different metal sheets;

[0034] (2) Add 0.246 g of thiourea to a mixed solution of 20 mL of deionized water and 60 mL of absolute ethanol, and magnetically stir for 30 min to form a homogeneous solution;

[0035] (3) Transfer the homogeneous solution into the polytetrafluoroethylene liner of the reaction kettle, and add the three metal sheets of pretreated nickel foam, copper foam and copper sheet. After the reaction kettle is sealed, place it in a drying oven and react at 160 °C for 4 h. After cooling to room temperature, take out the copper sheet with the active material grown on it, wash it several times with deionized water and absolute ethanol, and dry it at 60 °C for 10 h to obtain the copper sheet-supported nano copper-nickel sulfide negative electrode material.

[0036] (4) Cut the prepared copper sheet loaded with copper nickel sulfide to a size of 1.0 cm × 1.0 cm, cut a filter paper or separator with a size of 1.0 cm × 1.3 cm, and wrap the two sides and the bottom of the copper sheet loaded with sulfide in a U shape to obtain a coated electrode with a filter paper or separator coated with copper nickel sulfide loaded on the copper sheet.

[0037] Using the prepared copper sheet loaded with nano copper nickel sulfide electrode material as the working electrode, a platinum wire as the counter electrode, an Ag / AgCl electrode as the reference electrode, and a 6 mol L -1 aqueous KOH solution as the electrolyte, electrochemical performance tests were carried out in a three-electrode system. The tests included cyclic voltammetry curves and constant current charge-discharge curves, etc. The potential window for cyclic voltammetry tests was -1.2 to 0.2 V, and the scanning rate was 5 to 70 mV s -1 , and the potential window for constant current charge-discharge tests was -1.2 to 0 V. The cyclic stability test was carried out with the coated electrode as the working electrode in a three-electrode system for 750 constant current charge-discharge cycles at a current density of 100 mAcm -2 .

[0038] Figure 1 Figure [X] is the cyclic voltammetry curve of the prepared copper sheet loaded with nano copper nickel sulfide electrode material at different scanning rates. Each curve has obvious oxidation-reduction peaks, indicating that a Faraday pseudocapacitance reaction occurs; as the scanning rate increases, the peak current gradually increases and the shape basically remains unchanged, indicating good rate performance. Figure 2 Figure [X] is the constant current charge-discharge curve of this electrode at current densities of 5 and 10 mAcm -2 . The curve has obvious potential plateaus, further confirming that the active material undergoes oxidation-reduction reactions. According to the calculation of the discharge time, the areal specific capacitances of this electrode at 5 and 10 mAcm -2 are 12.26 and 12.06 Fcm -2 respectively, showing high capacitance.

[0039] Example 2

[0040] The difference between Example 2 and Example 1 is that in step (3), it was placed in a drying oven and reacted at 160 °C for 6 h. Other preparation conditions and processes were the same as those in Example 1, and a copper sheet loaded with nano copper nickel sulfide electrode material was obtained. From Figure 3 curve (a) of [Figure X], it can be seen that the areal specific capacitance of this electrode at 10 mAcm -2 is 7.77 F cm -2 .

[0041] Example 3

[0042] Example 3 is different from Example 1 in that in step (2), it is reacted in a drying oven at 160 °C for 8 h, and other preparation conditions and processes are the same as those in Example 1. A copper sheet-supported nano copper-nickel sulfide electrode material is obtained. From Figure 3 curve (b) of -2 , it can be seen that the areal specific capacitance of this electrode is 6.50 F cm -2 at 10 mA cm

[0043] Example 4

[0044] Example 4 is different from Example 1 in that in step (2), it is reacted in a drying oven at 160 °C for 10 h, and other preparation conditions and processes are the same as those in Example 1. A copper sheet-supported nano copper-nickel sulfide electrode material is obtained. From Figure 3 curve (c) of -2 , it can be seen that the areal specific capacitance of this electrode is 8.44 F cm -2 at 10 mA cm

[0045] Example 5

[0046] Example 5 is different from Example 2 in that in step (1), the copper foam is 6 × 2.2 cm 2 , and other preparation conditions and processes are the same as those in Example 2. A copper sheet-supported nano copper-nickel sulfide electrode material is obtained. From Figure 3 curve (b) of -2 , it can be seen that the areal specific capacitance of this electrode is 5.96 F cm -2 at 10 mA cm

[0047] Example 6

[0048] Example 6 is different from Example 1 in that in step (2), 0.243 g of thioacetamide is dissolved in 80 mL of deionized water, and after magnetic stirring for 30 min, a homogeneous solution is formed; in step (3), it is reacted in a drying oven at 90 °C for different times of 1, 2, 4, 6, and 8 h, and other preparation conditions and processes are the same as those in Example 1 to obtain a nano anode material. In step (4), the copper sheet loaded with copper-nickel sulfide is placed in the middle, and two pieces with a size of 1.0 cm × 1.0 cm 2 are nickel foam that sandwiches the two sides of the copper sheet to obtain a coated electrode with nickel foam-coated copper sheet loaded with copper-nickel sulfide. From Figure 4 curve, it can be seen that their areal specific capacitances are 9.20, 9.95, 8.14, 9.38, and 10.45 F cm -2 respectively at a current density of 5 mA cm -2 ; in addition, their areal specific capacitances are 7.50, 9.68, 7.41, 7.31, and 7.21 F cm -2 respectively at 10 mA cm-2 .

[0049] Figure 5 The coated electrode constructed by copper sheet loaded with nano copper nickel sulfide for cyclic stability test in the embodiment, and the stability curve at a high current density of 100 mA cm -2 when cycling 750 times. It can be seen from the figure that the initial areal specific capacitance of the coated electrode is 6.15 F cm -2 . In the first 20 cycles, the capacitance value rapidly increases to 22.16 F cm -2 , which should be the activation process of the material. When cycling to 400 times, the areal specific capacitance slowly increases to 31.78 F cm -2 ; During the cycles of 400 - 570 times, the capacitance value rapidly increases to 118.40 F cm -2 , which should be that the active material is deposited on the porous material and fully participates in the pseudocapacitance reaction; During the cycles of 570 - 750 times, the areal specific capacitance increases slowly with a certain degree of fluctuation; After 750 cycles, the areal specific capacitance is as high as 117.27 F cm -2 , which is 1906% of the initial capacitance value, showing surprisingly high cyclic stability. Thus, it can be seen that the prepared copper sheet loaded with nano copper nickel sulfide negative electrode material has high capacity, and the electrode coated with porous material has ultra-high cyclic stability, which can be applied to next-generation high-performance energy storage devices such as supercapacitors, lithium batteries, and lithium-sulfur batteries.

[0050] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description and ideas. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A preparation method of a copper-nickel sulfide electrode material, characterized in that, The preparation includes the following steps: (1) Ultrasonically pickling a nickel foam or nickel mesh, a copper foam or copper mesh, and a copper sheet with a certain area in 3M HCl solution for 10 - 15 min, then ultrasonically cleaning in deionized water 3 - 5 times until the solution is neutral, cleaning in absolute ethanol and drying; (2) Dissolving thiourea or thioacetamide with a concentration of 30 - 50 mM into a mixed solution with a volume ratio of deionized water to absolute ethanol of 1:3 or pure deionized water, and obtaining a uniform mixed solution after magnetic stirring; (3) Transferring the mixed solution into a polytetrafluoroethylene liner, adding the three different metal sheets pretreated in step (1), sealing the reaction kettle and carrying out a heating reaction in a forced-air drying oven, with the reaction temperature being 90 - 160 °C and the reaction time being 1 - 10 h; after the reaction, cooling to room temperature, and obtaining a copper sheet-supported nano copper-nickel sulfide electrode material after cleaning and drying; (4) Taking the copper sheet loaded with copper-nickel sulfide, and coating it with a porous material filter paper or diaphragm or nickel foam of a certain size, and the coating method is to coat the two sides of the copper substrate in a sandwich shape or to coat the two sides and the bottom of the copper substrate in a U shape to construct a coated electrode.

2. The preparation method according to claim 1, characterized in that, In step (1), the areas of the nickel foam or nickel mesh and the copper foam or copper mesh are 0.25 - 0.5 times and 0.25 - 1 times the area of the copper sheet respectively.

3. The preparation method according to claim 1, wherein, In step (4), the area of the porous material ≥ the area of the copper substrate.

4. A copper-nickel sulfide electrode material synthesized by the preparation method according to any one of claims 1-3, characterized in that, The prepared electrode material can be used as the negative electrode material of a supercapacitor.

5. Use of the coated electrode prepared by the method according to any one of claims 1-3, characterized in that, The prepared coated electrode can be applied to energy storage devices such as supercapacitors, lithium batteries, and lithium-sulfur batteries.

Images