A method for preparing transition metal oxide / sulfide electrode materials and supercapacitors

Abstract

This invention discloses a method for preparing a transition metal oxide / sulfide electrode material and a supercapacitor, belonging to the field of supercapacitor technology. The method includes: preparing a metal-organic framework material ZIF-67; using ZIF-67 and a sulfur source in a hydrothermal reaction to obtain a black solution; filtering the precipitate from the black solution onto a microporous membrane; washing and drying the precipitate to obtain Co3S4 / CoS; and heat-treating the Co3S4 / CoS in a muffle furnace to obtain the transition metal oxide / sulfide electrode material. This invention, based on ZIF-67 as a precursor, obtains the transition metal oxide / sulfide electrode material Co3S4 / CoS, which exhibits a high specific capacitance of 217.45 F g⁻¹ at 1 A g⁻¹, higher than that obtained using thioacetamide as a sulfur source in a hydrothermal reaction at 120°C for 48 h. After 2000 cycles, the capacity retention reaches 88.69%, demonstrating excellent cycling stability.

Description

Technical Field

[0001] This invention belongs to the field of supercapacitor technology, and more specifically, this invention relates to a method for preparing a transition metal oxide / sulfide electrode material and a supercapacitor. Background Technology

[0002] Supercapacitors are an advanced energy storage technology with promising applications. Both supercapacitors and batteries are electrochemical energy storage devices, sharing the common function of storing and releasing electrical energy through external circuits. They are widely used in peak shaving for new energy power, power supply for portable electronic devices, and power systems for electric vehicles. The differences are: Supercapacitors store energy physically, resulting in low energy density but extremely high power density, ultra-long cycle life, charge / discharge speeds in the seconds to minutes range, linear voltage decay, wide temperature adaptability, high safety, high cost per unit energy but long lifespan, and easier material recycling. Batteries, on the other hand, store energy chemically, resulting in high energy density but low power density, limited cycle life, hourly charge / discharge speeds, slow voltage decay, narrow temperature adaptability, and lower safety. A supercapacitor consists of four parts: a separator, electrode materials, current collectors, and an electrolyte.

[0003] Current supercapacitors suffer from several problems, such as poor cycle performance, low energy storage efficiency, and significant self-consumption. One crucial approach to improving supercapacitor performance is to modify its electrode materials, as this directly impacts the overall electrochemical characteristics of the device. ZIF-67 belongs to the cobalt-based metal-organic framework class. This structure features an open mesh-like structure with a large surface area, forming a hollow porous structure that enhances the exposure of active sites. This results in better chemical stability, excellent electrochemical properties, and flexibility, making it highly promising for various applications. The energy storage mechanism of Co3S4 / CoS is primarily based on pseudocapacitance, utilizing Co... 2+ / Co 3+ and S 2- Co3S4 / CoS stores charge through redox reactions, and its theoretical specific capacity is much higher than that of traditional double-layer carbon materials (such as activated carbon). Traditional supercapacitors are limited by the double-layer mechanism and have low energy density. Co3S4 / CoS increases the energy density to near the level of lithium-ion batteries through pseudocapacitive reactions, but there is still a gap. Summary of the Invention

[0004] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0005] To achieve these and other advantages according to the present invention, the present invention provides a method for preparing a transition metal oxide / sulfide electrode material, comprising the following steps:

[0006] Step 1: Prepare metal-organic framework material ZIF-67 using 2-methylimidazole and a cobalt source;

[0007] Step 2: A black solution is obtained by hydrothermal reaction of metal-organic framework material ZIF-67 and sulfur source. The precipitate from the black solution is filtered onto a microporous membrane, washed multiple times, and dried to obtain Co3S4 / CoS.

[0008] Step 3: Heat-treat Co3S4 / CoS in a muffle furnace to obtain transition metal oxide / sulfide electrode material.

[0009] Preferably, in step one, the specific method for preparing the metal-organic framework material ZIF-67 using 2-methylimidazole and a cobalt source includes: dissolving 2-methylimidazole in methanol to obtain a clear and transparent solution A; dissolving the cobalt source in methanol to obtain solution B; stirring for more than 2 hours; mixing solution A and solution B; allowing the mixture to stand at 25°C for 12 to 36 hours; and after filtration, washing, and drying at 60°C to 90°C, obtaining the metal-organic framework material ZIF-67.

[0010] Preferably, the cobalt source is cobalt nitrate hexahydrate;

[0011] The ratio of 2-methylimidazole to methanol is 0.03 mol to 0.05 mol: 100 mL to 300 mL; the ratio of cobalt nitrate hexahydrate to methanol is 0.01 mol: 100 mL to 300 mL.

[0012] Preferably, the specific method of step two includes: adding metal-organic framework material ZIF-67 and sulfur source to ethanol, sonicating for 10 min to 20 min until they are fully dispersed to obtain a solution; placing the solution in a high-pressure reactor and reacting at 120℃ to 160℃ for 12 h to 48 h to obtain a black solution;

[0013] The precipitate in the black solution was filtered onto a microporous membrane by vacuum filtration and washed multiple times with anhydrous ethanol. The microporous membrane was then placed in a vacuum drying oven at a temperature of 70℃~90℃ for 12h~36h to obtain Co3S4 / CoS.

[0014] Preferably, the sulfur source is thioacetamide or thiourea.

[0015] Preferably, the ratio of ethanol, metal-organic framework material ZIF-67, and sulfur source is 5 mL~7 mL: 10 mg~13 mg: 19 mg~20 mg.

[0016] Preferably, in step three, the heat treatment temperature is 400℃~500℃, the heating rate is 2℃ / min~4℃ / min, and the holding time is 1h~3h.

[0017] Preferably, in step two, before the hydrothermal reaction of the metal-organic framework material ZIF-67 and the sulfur source, 5wt%~25wt% of TiO2-coated NiO powder, accounting for 5wt%~25wt% of the mass of the metal-organic framework material ZIF-67, is added to the reaction system; the preparation method of the TiO2-coated NiO powder includes:

[0018] S21. Mix nickel nitrate solution and urea and add them to a high-pressure reactor. React hydrothermally at 110℃~140℃ for 6h~12h. Filter out the precipitate and calcine the precipitate in air at 300℃~400℃ for 1h~4h to obtain NiO.

[0019] S22. NiO is dispersed in anhydrous ethanol to obtain a NiO suspension. The reaction vessel containing the NiO suspension is placed in a constant temperature water bath, and the temperature is set to 30°C~40°C. Stirring is started. Tetrabutyl titanate is mixed with an equimolar amount of acetylacetone and stirred for 20min~40min to obtain a mixed solution. The mixed solution is then diluted with anhydrous ethanol to obtain solution A. Deionized water, anhydrous ethanol and catalyst are mixed to obtain solution B. Under continuous stirring, equal volumes of solution A and solution B are added dropwise to the NiO suspension at a constant rate. After the addition is complete, the reaction is stirred at a constant temperature for 4h~12h. Stirring is stopped and the mixture is allowed to stand for 12h~24h. The product is separated by centrifugation. The washed product is dried in a vacuum drying oven at 60°C~80°C for 6h~12h to obtain amorphous TiO2-coated NiO precursor powder.

[0020] S23. Place the amorphous TiO2-coated NiO precursor powder in a muffle furnace, heat it to 400°C~600°C at a rate of 1°C / min~5°C / min, calcine for 2h~4h, cool and grind to obtain TiO2-coated NiO powder.

[0021] Preferably, in step S21, the molar ratio of nickel nitrate to urea is 1:3~5, and the concentration of the nickel nitrate solution is 0.01M~0.2M.

[0022] In S22, the ratio of NiO to anhydrous ethanol is 1g~10g:100mL~400mL;

[0023] The mass ratio of NiO to tetrabutyl titanate is 1~10:20:100;

[0024] In solution B, the catalyst is 0.2M nitric acid, and the ratio of deionized water, anhydrous ethanol and catalyst is 10mL~20mL:5mL~10mL:1mL~2mL.

[0025] A supercapacitor, wherein the transition metal oxide / sulfide electrode material is prepared by the above-described method for preparing transition metal oxide / sulfide electrode materials.

[0026] The present invention includes at least the following beneficial effects: The present invention obtains the transition metal oxide / sulfide electrode material Co3S4 / CoS based on ZIF-67 as a precursor. The results show that the transition metal oxide / sulfide electrode material obtained by using thiourea as the sulfur source and hydrothermally reacting at 160℃ for 24h has the best performance. The specific capacitance is as high as 217.45F g⁻¹ at 1A g⁻¹, which is twice as high as the specific capacitance of the transition metal oxide / sulfide electrode material obtained by using thioacetamide as the sulfur source and hydrothermally reacting at 120℃ for 48h. After 2000 cycles, the capacity retention rate reaches 88.69%, showing good cycling stability.

[0027] This invention utilizes the transition metal oxide / sulfide electrode material Co3S4 / CoS, obtained through a hydrothermal reaction at 160℃ for 24 hours, as the positive electrode material, and YP50 activated carbon to construct an asymmetric supercapacitor. The Co3S4 / CoS / / AC achieves an energy density of 4.0 Wh kg⁻¹ at a power density of 700 W kg⁻¹; even at a high power density of 7000 W kg⁻¹, it maintains an energy density of 2.3 Wh kg⁻¹. After 2000 cycles at a scan rate of 100 mV s⁻¹, the device exhibits a capacity retention of 116.09%, demonstrating excellent cycling performance.

[0028] This invention prepares Co3S4 / CoS materials using ZIF-67 as a template, which not only increases the contact area between the material and the electrolyte but also provides a fast channel for ion diffusion, thereby increasing the energy storage capacity. This pseudocapacitive mechanism stores more energy than the physical adsorption of traditional double-layer capacitors, and the energy density can approach the level of a battery. The large atomic radius of sulfur atoms can reduce the volume expansion during cycling, and the stable crystal structure can maintain a high capacity even after thousands of charge-discharge cycles.

[0029] This invention also incorporates TiO2-coated NiO powder into Co3S4 / CoS. The results show that the incorporation of TiO2-coated NiO powder further improves the capacity retention and specific capacitance of the transition metal oxide / sulfide electrode material. NiO coated with a TiO2 layer (especially well-crystallized TiO2 after calcination) has high mechanical strength. The TiO2 layer acts as a buffer and constraint layer, effectively suppressing the volume expansion of the NiO core and preventing particle breakage and pulverization. The NiO surface is in direct contact with the electrolyte, and an unstable SEI film will form in the early stage of cycling. During subsequent volume changes, the SEI film will continuously break and repair itself, continuously consuming electrolyte and active lithium ions, leading to increased impedance and irreversible capacity decay. TiO2 has excellent chemical stability and a wide electrochemical window. The shell composed of TiO2 can form a more stable and denser SEI film. This stable interface prevents direct side reactions between NiO and the electrolyte, reducing the loss of active material and the increase in impedance. During long-term cycling, the TiO2 shell can physically block the dissolution of NiO and confine it within the shell. Simultaneously, it prevents NiO nanoparticles from re-aggregating into larger particles during cycling, avoiding a reduction in the reaction area and a decrease in the capacity of the electrode material. Pure NiO has poor conductivity, and the drastic volume changes during repeated charge-discharge cycles can lead to the pulverization and shedding of the active material, resulting in an actual specific capacitance far lower than the theoretical value. However, the TiO2 coating layer can prevent the agglomeration of NiO nanoparticles during preparation and cycling, allowing more NiO surface atoms to be exposed and effectively participate in the Faraday reaction, thereby improving the utilization rate of NiO. The uniform TiO2 layer provides a good permeation channel for electrolyte ions and an interface for reaction with NiO nuclei. Compared with pure NiO, which is prone to agglomeration, this structure has a more regular and shorter ion diffusion path, enabling ions to reach the active sites more quickly, thereby improving the rate performance and effective capacity of the final TiO2-NiO Co3S4 / CoS composite material. In the final TiO2-NiO-doped Co3S4 / CoS composite material, the TiO2 coating layer provides a more efficient ion migration interface for Co3S4 / CoS. The TiO2 coating layer and the Co3S4 / CoS matrix form a heterostructure, which optimizes the interfacial charge distribution and enhances electronic conductivity. During the hydrothermal process, NiO serves as the substrate, and the TiO2 coating layer works synergistically with ZIF-67 to regulate the nucleation and growth of Co3S4 / CoS, forming a more uniform TiO2-NiO-doped Co3S4 / CoS composite material. NiO itself has pseudocapacitive properties, which synergize with the sulfide active sites of Co3S4 / CoS, increasing the specific capacitance of the transition metal oxide / sulfide electrode material.

[0030] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0031] Figure 1 XRD pattern of ZIF-67, a metal-organic framework material prepared in Example 1;

[0032] Figure 2 The XRD pattern of Co3S4 / CoS prepared in Example 1;

[0033] Figure 3 SEM image of ZIF-67, the metal-organic framework material prepared in Example 1;

[0034] Figure 4 SEM image of 120℃-48h-TAA prepared in Example 1;

[0035] Figure 5 SEM image of 120℃-48h-TU prepared in Example 2;

[0036] Figure 6 SEM image of 160℃-24h-TU prepared in Example 3;

[0037] Figure 7 The 120℃-48h-TAA prepared in Example 1, the 120℃-12h-TAA prepared in Example 4, and the 120℃-24h-TAA prepared in Example 5 were tested at 10mV s. -1 The following is a CV diagram;

[0038] Figure 8 The 120℃-48h-TAA prepared in Example 1, the 120℃-12h-TAA prepared in Example 4, and the 120℃-24h-TAA prepared in Example 5 were analyzed at a scanning density of 1 Ag. -1 The following GCD diagram;

[0039] Figure 9 EIS chromatograms of 120℃-48h-TAA prepared in Example 1, 120℃-12h-TAA prepared in Example 4, and 120℃-24h-TAA prepared in Example 5;

[0040] Figure 10 The 120℃-48h-TU prepared in Example 2, the 120℃-12h-TU prepared in Example 6, and the 120℃-24h-TU prepared in Example 7 were tested at 10mV s. -1 The following is a CV diagram;

[0041] Figure 11The 120℃-48h-TU prepared in Example 2, the 120℃-12h-TU prepared in Example 6, and the 120℃-24h-TU prepared in Example 7 were tested at a scanning density of 1 Ag. -1 The following GCD diagram;

[0042] Figure 12 EIS chromatograms of the 120℃-48h-TU prepared in Example 2, the 120℃-12h-TU prepared in Example 6, and the 120℃-24h-TU prepared in Example 7;

[0043] Figure 13 The 120℃-48h-TU prepared for Example 2 was subjected to a temperature of 10mV s. -1 ~100mV s -1 CV graph at scan speed;

[0044] Figure 14 The 120℃-48h-TU prepared in Example 2 was in 1A g -1 ~10A g -1 GCD plot at current density;

[0045] Figure 15 The ratio of specific capacitance to current density for the 120℃-48h-TU prepared in Example 2 is shown in the graph.

[0046] Figure 16 The 160℃-24h-TU prepared for Example 3 was subjected to a temperature of 10mV s. -1 ~100mV s -1 CV graph at scan speed;

[0047] Figure 17 The 160℃-24h-TU prepared in Example 3 was in 1A g -1 ~10A g -1 GCD plot at current density;

[0048] Figure 18 The ratio of specific capacitance to current density for the 160℃-24h-TU prepared in Example 3 is shown in the graph.

[0049] Figure 19 The graph shows the change in capacity retention of the 160℃-24h-TU prepared in Example 3;

[0050] Figure 20 YP50 activated carbon at 1A g -1 The following GCD diagram;

[0051] Figure 21 The 160℃-24h-TU prepared in Example 3 was reacted with activated carbon YP50 at 10mV s -1 The following is a CV diagram;

[0052] Figure 22 GCD diagrams of Co3S4 / CoS / / AC constructed from 160℃-24h-TU and activated carbon YP50 prepared in Example 3 at different voltages;

[0053] Figure 23 The CV curves of Co3S4 / CoS / / AC constructed from 160℃-24h-TU and activated carbon YP50 prepared in Example 3 at different scan rates;

[0054] Figure 24 GCD diagrams of Co3S4 / CoS / / AC constructed from 160℃-24h-TU and activated carbon YP50 prepared in Example 3 at different current densities;

[0055] Figure 25 The graph shows the ratio of specific capacitance to current density of Co3S4 / CoS / / AC constructed from 160℃-24h-TU and activated carbon YP50 prepared in Example 3.

[0056] Figure 26 The graph shows the relationship between the energy density and specific power of the Co3S4 / CoS / / AC constructed from 160℃-24h-TU and activated carbon YP50 prepared in Example 3;

[0057] Figure 27 Impedance diagram of Co3S4 / CoS / / AC constructed from 160℃-24h-TU and activated carbon YP50 prepared in Example 3;

[0058] Figure 28 The Co3S4 / CoS / / AC constructed from TU prepared in Example 3 at 160℃-24h and activated carbon YP50 was subjected to a temperature of 100mV / s. -1 The capacity retention rate graph below. Detailed Implementation

[0059] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0060] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0061] Example 1

[0062] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0063] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in an equal volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solutions A and B, let stand at 25°C for 24 hours, and after filtration, washing, and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0064] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67 and 195 mg of thioacetamide (TAA) to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TAA solution. Place the ZIF / TAA solution in a high-pressure reactor and react at 120 °C for 48 h to obtain a black solution. Filter the precipitate from the black solution onto a microporous membrane using vacuum filtration, and wash it multiple times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven at 80 °C for 24 h to obtain Co3S4 / CoS.

[0065] Step 3: Heat-treat Co3S4 / CoS in a muffle furnace to obtain a transition metal oxide / sulfide electrode material, denoted as 120℃-48h-TAA.

[0066] Example 2

[0067] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0068] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in an equal volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solutions A and B, let stand at 25°C for 24 hours, and after filtration, washing, and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0069] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67 and 198 mg of thiourea (TU) to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TU solution. Place the ZIF / TU solution in a high-pressure reactor and react at 120 °C for 48 h to obtain a black solution. Filter the precipitate from the black solution onto a microporous membrane by vacuum filtration, and wash it several times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven, set the temperature to 80 °C, and dry for 24 h to obtain Co3S4 / CoS.

[0070] Step 3: Heat-treat Co3S4 / CoS in a muffle furnace to obtain a transition metal oxide / sulfide electrode material, denoted as 120℃-48h-TU.

[0071] Example 3

[0072] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0073] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in an equal volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solutions A and B, let stand at 25°C for 24 hours, and after filtration, washing, and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0074] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67 and 198 mg of thiourea (TU) to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TU solution. Place the ZIF / TU solution in a high-pressure reactor and react at 160℃ for 24 h to obtain a black solution. Filter the precipitate from the black solution onto a microporous membrane by vacuum filtration, and wash it several times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven, set the temperature to 80℃, and dry for 24 h to obtain Co3S4 / CoS.

[0075] Step 3: Heat-treat Co3S4 / CoS in a muffle furnace to obtain a transition metal oxide / sulfide electrode material, denoted as 160℃-24h-TU.

[0076] Example 4

[0077] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0078] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in an equal volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solutions A and B, let stand at 25°C for 24 hours, and after filtration, washing, and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0079] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67 and 195 mg of thioacetamide (TAA) to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TAA solution. Place the ZIF / TAA solution in a high-pressure reactor and react at 120 °C for 12 h to obtain a black solution. Filter the precipitate from the black solution onto a microporous membrane by vacuum filtration, and wash it several times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven, set the temperature to 80 °C, and dry for 24 h to obtain Co3S4 / CoS.

[0080] Step 3: Heat-treat Co3S4 / CoS in a muffle furnace to obtain a transition metal oxide / sulfide electrode material, denoted as 120℃-12h-TAA.

[0081] Example 5

[0082] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0083] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in an equal volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solutions A and B, let stand at 25°C for 24 hours, and after filtration, washing, and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0084] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67 and 195 mg of thioacetamide (TAA) to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TAA solution. Place the ZIF / TAA solution in a high-pressure reactor and react at 120 °C for 24 h to obtain a black solution. Filter the precipitate from the black solution onto a microporous membrane by vacuum filtration, and wash it several times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven, set the temperature to 80 °C, and dry for 24 h to obtain Co3S4 / CoS.

[0085] Step 3: Heat-treat Co3S4 / CoS in a muffle furnace to obtain a transition metal oxide / sulfide electrode material, denoted as 120℃-24h-TAA.

[0086] Example 6

[0087] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0088] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in an equal volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solutions A and B, let stand at 25°C for 24 hours, and after filtration, washing, and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0089] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67 and 198 mg of thiourea (TU) to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TU solution. Place the ZIF / TU solution in a high-pressure reactor and react at 120 °C for 12 h to obtain a black solution. Filter the precipitate from the black solution onto a microporous membrane using vacuum filtration, and wash it multiple times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven at 80 °C for 24 h to obtain Co3S4 / CoS.

[0090] Step 3: Heat-treat Co3S4 / CoS in a muffle furnace to obtain a transition metal oxide / sulfide electrode material, denoted as 120℃-12h-TU.

[0091] Example 7

[0092] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0093] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in an equal volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solutions A and B, let stand at 25°C for 24 hours, and after filtration, washing, and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0094] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67 and 198 mg of thiourea (TU) to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TU solution. Place the ZIF / TU solution in a high-pressure reactor and react at 120 °C for 24 h to obtain a black solution. Filter the precipitate from the black solution onto a microporous membrane using vacuum filtration, and wash it multiple times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven at 80 °C for 24 h to obtain Co3S4 / CoS.

[0095] Step 3: Heat-treat Co3S4 / CoS in a muffle furnace to obtain a transition metal oxide / sulfide electrode material, denoted as 120℃-24h-TU.

[0096] Example 8

[0097] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0098] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in an equal volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solutions A and B, let stand at 25°C for 24 hours, and after filtration, washing, and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0099] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67, 198 mg of thiourea (TU), and 30 mg of TiO2-coated NiO powder to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TU / TiO2-NiO solution; place the ZIF / TU / TiO2-NiO solution in a high-pressure reactor and react at 160℃ for 24 h. Filter the precipitate from the solution after the reaction onto a microporous membrane, and wash it multiple times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven, set the temperature to 80℃, and dry for 24 h to obtain TiO2-NiO-doped Co3S4 / CoS.

[0100] The preparation methods for TiO2-coated NiO powder include:

[0101] S21. Mix 0.2M nickel nitrate solution and urea and add them to a high-pressure reactor. The molar ratio of nickel nitrate to urea is 1:4. React hydrothermally at 120℃ for 6 hours. Filter out the precipitate and calcine the precipitate at 350℃ for 3 hours in air atmosphere to obtain NiO.

[0102] S22. Disperse 10g NiO in 400mL of anhydrous ethanol to obtain a NiO suspension. Place the three-necked flask containing the NiO suspension in a constant temperature water bath at 40℃ and start stirring at 200rpm. Mix 85g tetrabutyl titanate (0.25mol) with 0.25mol acetylacetone and stir at 200rpm for 30min to obtain a mixed solution. Dilute the mixed solution with 80mL of anhydrous ethanol and bring the volume to 200mL to obtain solution A. Mix 140mL of deionized water, 50mL of anhydrous ethanol, and 10mL of 0.2M nitric acid and bring the volume to 200mL to obtain solution B. While stirring continuously, mix 200mL of solution A with 200mL of... Solution B was added dropwise to the NiO suspension at a rate of 2 mL / min. After the addition was complete, the mixture was stirred at 40 °C for 6 h. Stirring was stopped and the mixture was allowed to stand for 24 h. The product was separated by centrifugation and the washed product was dried in a vacuum drying oven at 80 °C for 12 h to obtain amorphous TiO2-coated NiO precursor powder.

[0103] S23. The amorphous TiO2-coated NiO precursor powder is heated to 450°C in a muffle furnace at a rate of 5°C / min and calcined for 3 hours. After cooling, it is ground to obtain TiO2-coated NiO powder.

[0104] Step 3: Heat-treat the TiO2-NiO-doped Co3S4 / CoS in a muffle furnace to obtain transition metal oxide / sulfide electrode material.

[0105] Example 9

[0106] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0107] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in an equal volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solutions A and B, let stand at 25°C for 24 hours, and after filtration, washing, and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0108] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67, 198 mg of thiourea (TU), and 6 mg of TiO2-coated NiO powder to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TU / TiO2-NiO solution; place the ZIF / TU / TiO2-NiO solution in a high-pressure reactor and react at 160℃ for 24 h. Filter the precipitate from the solution after the reaction onto a microporous membrane, and wash it multiple times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven, set the temperature to 80℃, and dry for 24 h to obtain TiO2-NiO-doped Co3S4 / CoS.

[0109] The preparation method of TiO2-coated NiO powder is the same as that in Example 8.

[0110] Step 3: Heat-treat the TiO2-NiO-doped Co3S4 / CoS in a muffle furnace to obtain transition metal oxide / sulfide electrode material.

[0111] Comparative Example 1

[0112] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0113] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in an equal volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solutions A and B, let stand at 25°C for 24 hours, and after filtration, washing, and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0114] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67, 198 mg of thiourea (TU), and 30 mg of TiO2 powder to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TU / TiO2 solution; place the ZIF / TU / TiO2 solution in a high-pressure reactor and react at 160℃ for 24 h. Filter the precipitate from the solution after the reaction onto a microporous membrane, and wash it multiple times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven, set the temperature to 80℃, and dry for 24 h to obtain TiO2-doped Co3S4 / CoS.

[0115] Step 3: Heat-treat the TiO2-doped Co3S4 / CoS in a muffle furnace to obtain transition metal oxide / sulfide electrode material.

[0116] Comparative Example 2

[0117] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0118] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in an equal volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solutions A and B, let stand at 25°C for 24 hours, and after filtration, washing, and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0119] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67, 198 mg of thiourea (TU), and 30 mg of NiO powder to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TU / NiO solution. Place the ZIF / TU / NiO solution in a high-pressure reactor and react at 160℃ for 24 h. Filter the precipitate from the solution after the reaction onto a microporous membrane, and wash it multiple times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven, set the temperature to 80℃, and dry for 24 h to obtain NiO-doped Co3S4 / CoS.

[0120] Step 3: NiO-doped Co3S4 / CoS is placed in a muffle furnace for heat treatment to obtain transition metal oxide / sulfide electrode material.

[0121] Comparative Example 3

[0122] A method for preparing a transition metal oxide / sulfide electrode material includes the following steps:

[0123] Step 1: Dissolve 3.284 g of 2-methylimidazole in 200 mL of methanol to obtain a clear and transparent solution A. Dissolve 2.9102 g of cobalt nitrate hexahydrate in the same volume of methanol to obtain solution B. After stirring for more than 2 hours, mix solution A and solution B, let stand at 25°C for 24 hours, and after filtration, washing and drying at 80°C, obtain the metal-organic framework material ZIF-67.

[0124] Step 2: Measure 60 mL of ethanol into a beaker, add 120 mg of metal-organic framework material ZIF-67, 198 mg of thiourea (TU), 20 mg of TiO2 powder, and 10 mg of NiO powder to the beaker, and sonicate for 15 min until fully dispersed to obtain a ZIF / TU / TiO2 / NiO solution; place the ZIF / TU / TiO2 / NiO solution in a high-pressure reactor and react at 160℃ for 24 h. Filter the precipitate from the solution after the reaction onto a microporous membrane, and wash it multiple times with anhydrous ethanol. Place the microporous membrane in a vacuum drying oven, set the temperature to 80℃, and dry for 24 h to obtain Co3S4 / CoS doped with TiO2 and NiO.

[0125] Step 3: Heat-treat Co3S4 / CoS doped with TiO2 and NiO in a muffle furnace to obtain transition metal oxide / sulfide electrode material.

[0126] The transition metal oxide / sulfide electrode materials obtained in the above examples and comparative examples were respectively prepared as positive electrodes. The specific methods included:

[0127] First, the active material was mixed with acetylene black and polyvinylidene fluoride in a mass ratio of 8:1:1 and placed in a mortar. Next, after thorough grinding and mixing, 2 mL of N-methyl-2-pyrrolidone was added, and the mixture was ground thoroughly to obtain an electrode slurry. Using a small brush, the prepared slurry was evenly coated onto an area of ​​2 cm². 2 The electrode paste was then applied to nickel foam. The nickel foam coated with the electrode paste was then placed in a vacuum oven and dried overnight at 80°C to obtain the positive electrode.

[0128] Figure 1 The diffraction peaks formed by the metal-organic framework material ZIF-67 prepared in Example 1 are shown to be almost identical to the standard diffraction peak positions in the range of 5° to 40°, proving the successful synthesis of the precursor. Figure 2 The XRD pattern of the Co3S4 / CoS microcubes prepared in Example 1 is shown. Figure 2We can clearly see sharp diffraction signals, which are basically consistent with the standard cards of Co3S4 (PDF#74-0138) and CoS (PDF#75-0605), proving that the target product has been successfully synthesized. The strong diffraction peaks at 2θ = 31.5°, 38.2°, 41.8°, 50.3°, 55.2°, and 58.8° correspond to the (311), (400), (331), (511), (440), and (442) crystal planes of Co3S4, while the strong diffraction peaks at 2θ = 30.5°, 35.2°, 46.9°, 54.2°, 63.5°, and 66.1° correspond to the (100), (101), (102), (110), (200), and (112) crystal planes of CoS. The presence of two broad peaks in the middle indicates the coexistence of multiple phases, suggesting a two-phase composite system containing Co. 3+ and Co 2+ Two valence states.

[0129] The morphology of the electrode material was obtained by SEM characterization. The SEM image of the metal-organic framework material ZIF-67 at a scale of 5 μm is shown below. Figure 3 As shown, it exhibits a rhombic dodecahedral configuration, with good crystal homogeneity and complete crystal faces.

[0130] Next, SEM images of the three sets of Co3S4 / CoS from Examples 1-3 were tested, as shown below. Figure 4 , Figure 5 , Figure 6 As shown. Among them. Figure 4 The Co3S4 / CoS obtained by hydrothermal reaction at 120℃ for 48 hours with TAA as the sulfur source has poor crystal uniformity and severe agglomeration. Figure 5 The Co3S4 / CoS obtained using TU as the sulfur source after a hydrothermal reaction at 120℃ for 48 hours exhibits more regular and dispersed crystals with a size less than 2 μm compared to those obtained using TAA as the sulfur source. Figure 6 The Co3S4 / CoS obtained by hydrothermal reaction at 160℃ for 24 hours with TU as the sulfur source exhibits a rhombic polyhedron shape, complete crystallinity, and the most dispersed volume compared to the previous two groups, thus possessing the best electrochemical performance.

[0131] For Examples 1, 4, and 5, the electrochemical performance of Co3S4 / CoS sulfides prepared at different hydrothermal times (12h, 24h, and 48h) using TAA as the sulfur source at 120℃ was tested in a three-electrode system (using a Shanghai Zhenhua CHI660D electrochemical workstation). Figure 7 The three groups of materials have a voltage range of 0V to 0.6V and a voltage of 10mV s. -1The cyclic voltammograms below show two pairs of clear redox reaction peaks on each CV curve. During this process, the integral area of ​​the image varies greatly, with the 48h group having the largest area, indicating strong charge storage capacity and high electrode capacity. Figure 8 To scan at a density of 1A g -1 The GCD curves were obtained below, and during this process, the specific capacitances of the three materials were 102.73 Fg. -1 171.64F g -1 207.01F g -1 This indicates that, under the same conditions, the active material with a hydrothermal reaction time of 48 h has a higher specific capacitance than other reaction times. Figure 9 The figures show the impedance curves for three sets of materials. The semicircle diameter in the high-frequency region reflects the resistance value of charge transfer, while the slope of the straight line in the low-frequency band directly relates to the magnitude of the diffusion resistance. Observing the impedance over 48 hours, it can be seen that the slope in the high-frequency region is larger, and the electrodiffusion resistance is smaller. This indicates that the charge transfer efficiency is higher. This can be understood as follows: under a certain dosage, by increasing the reaction time, the ZIF-67 precursor can fully react with TAA, thereby shaping a more complete Co3S4 / CoS crystal structure and improving the chemical properties of the material surface.

[0132] Changes in the sulfur source can also affect the performance of the final product. The electrochemical performance of thiourea (TU) was investigated at the same hydrothermal reaction temperature for 12 h, 24 h, and 48 h (Examples 2, 6, and 7), still conducted in a three-electrode system. Figure 10 The three groups of materials have a voltage range of 0V to 0.6V and a voltage of 10mV s. -1 The cyclic voltammogram below is the same as when TAA is used as the sulfur source, with two pairs of redox peaks. The calculated integral area of ​​24h is greater than that of 48h, which may be due to incomplete sulfidation leading to excessive precursor residues and creating a false impression of "artificial high" values. Figure 11 Three groups of active materials were scanned at a density of 1 A g. -1 The GCD curves were obtained below, and during this process, the specific capacitances of the three material groups were 172.18 F g. -1 206.73F g -1 ,207.10F g -1 Compared with TAA as a sulfur source, TU as a sulfur source has a slightly better specific capacitance. This may be related to the difference in decomposition kinetics and chemical activity of TU. The sulfur release rate of TU is more gradual and stable than that of TAA, which is conducive to the more uniform coordination of sulfur atoms with cobalt ions of ZIF-67. At the same time, it slightly increases the conductivity of the active material, thus producing a weak positive effect. Figure 12The curves for the impedance tests of the three groups of materials show that the 48h group has the largest slope in the high-frequency region, the smallest diffusion impedance, and the best charge transfer efficiency. In summary, the electrochemical performance is best when the hydrothermal reaction is carried out at 120℃ with TU as the sulfur source. This is attributed to the fact that the 48h sulfidation makes the Co3S4 / CoS crystals more complete and reduces surface defects.

[0133] Figure 13 The 120℃-48h-TU prepared in Example 2 was shown to operate at 10 mVs in the range of 0V to 0.6V. -1 ~100mVs -1 The current-voltage curve below. Figure 14 The gamma-coefficient of change (GCD) of the hydrothermal reaction 120℃-48h-TU at different current densities is shown. At 1A g... -1 2Ag -1 ,3A g -1 5A g -1 10A g -1 The specific capacitances at the following values ​​are 207.10 F g. -1 98.55F g -1 63.27F g -1 35.64Fg -1 15.82F g -1 .like Figure 15 As shown, the specific capacitance decreases with increasing current density, reflecting a weakening ability to maintain capacitance at high rates.

[0134] Electrochemical data of the 160℃-24h-TU prepared in Example 3 are as follows: Figure 16 , Figure 17 , Figure 18 As shown, Figure 16 For 160℃-24h-TU within the range of 0V~0.6V, 10mV s -1 ~100mV s -1 The following is a diagram of Fu'an. Figure 17 The GCD of 160℃-24h-TU at different current densities is shown. During this process, at 1A g... -1 2 A g -1 ,3A g -1 5A g -1 10A g -1 The specific capacitances at the following values ​​are 217.45 F g. -1 102.91F g -1 65.45 F g -1 36.73F g -1 ,16F g -1 like Figure 18 As shown.

[0135] The 160℃-24h-TU prepared in Example 3 was used at 100mV s -1 A 2000-cycle charge-discharge test was conducted at a scan rate, and the retention rate change was recorded every 100 cycles. The results are as follows: Figure 19 As shown, in the initial stage, the specific capacitance gradually increases as the active material slowly comes into full contact with the electrolyte. When the number of cycles increases, the capacitance retention rate at 160℃-24h-TU is 88.69%.

[0136] The 160℃-24h-TU prepared in Example 3 was selected as the positive electrode material and YP50 activated carbon was selected as the negative electrode material to construct an asymmetric supercapacitor with a two-electrode system. Its performance characteristics were comprehensively examined by implementing cyclic voltammetry, constant current charge-discharge experiments and AC impedance tests. Figure 20 For the GCD curve of Co3S4 / CoS / / AC, calculate AC at 1A g. -1 The specific capacitance at that time was 77.9 F g. -1 . Figure 21 The CV curves for Co3S4 / CoS / / AC are shown. A two-electrode system was constructed for electrochemical performance testing. The optimal voltage window was determined to be 1.4V using constant current charge-discharge testing. Figure 22 As shown, cyclic voltammetry and constant current charge-discharge tests were performed based on this.

[0137] Cyclic voltammetry at different scan rates within the optimal voltage window of 1.4V is shown below. Figure 23 As shown, the redox peaks are clearly visible in the redox reaction, proving that this asymmetric supercapacitor is dominated by pseudocapacitive behavior. Figure 24 This demonstrates the constant current charge-discharge process under various current density settings. The five curves are roughly symmetrical, and their specific capacity changes are plotted as shown below. Figure 25 As shown, the specific capacitance at the five current densities is 14.71 F g. -1 12.14F g -1 10.93F g -1 10.36F g -1 8.57F g -1 The relationship between energy density and specific power of Co3S4 / CoS / / AC is as follows: Figure 26 As shown, at 700 W kg -1 1400W kg -1 2100W kg -1 3500W kg -1 7000W kg -1 At a power density of , the energy densities are 4.0 Wh kg. -1 3.3Wh kg-1 2.9Wh kg -1 2.8Wh kg -1 2.3Wh kg -1 . Figure 27 The AC impedance curve of Co3S4 / CoS / / AC is shown. The slope is large in the high-frequency region, so the impedance is small, showing a relatively good impedance level. Figure 28 It exhibits a value of 100mV s -1 After 2000 cycles at a scanning speed, the capacitance retention of the asymmetric supercapacitor and the changes in the CV curve before and after the cycles were observed. After 2000 cycles, the capacitance retention of the asymmetric supercapacitor reached 116.09%, which shows that the assembled asymmetric supercapacitor has good cycle stability.

[0138] The capacity retention (after 2000 cycles) and specific capacitance (1 A g) of the transition metal oxide / sulfide electrode materials obtained in Examples 3, 8, 9, 1, 2, and 3 were measured respectively. -1 By comparing the results, the following table was obtained:

[0139] Table 1. Comparison of Capacitance Retention and Specific Capacitance of Each Sample

[0140]

[0141] As can be seen from Table 1, the transition metal oxide / sulfide electrode material prepared by NiO powder doped with TiO2 has higher capacity retention and specific capacitance, exhibiting superior electrochemical performance. When applied as the cathode material of supercapacitors, it can significantly improve the electrical performance of supercapacitors.

[0142] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.

[0143] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for preparing a transition metal oxide / sulfide electrode material, characterized in that, Includes the following steps: Step 1: Prepare metal-organic framework material ZIF-67 using 2-methylimidazole and a cobalt source; Step 2: A hydrothermal reaction was carried out using metal-organic framework material ZIF-67 and a sulfur source. TiO2-coated NiO powder, accounting for 5wt%~25wt% of the mass of metal-organic framework material ZIF-67, was added to the reaction system. The hydrothermal reaction yielded a black solution. The precipitate from the black solution was filtered onto a microporous membrane, washed multiple times, and dried to obtain Co3S4 / CoS doped with TiO2-NiO. The methods for preparing TiO2-coated NiO powder include: S21. Mix nickel nitrate solution and urea and add them to a high-pressure reactor. React hydrothermally at 110℃~140℃ for 6h~12h. Filter out the precipitate and calcine the precipitate in air at 300℃~400℃ for 1h~4h to obtain NiO. S22. NiO is dispersed in anhydrous ethanol to obtain a NiO suspension. The reaction vessel containing the NiO suspension is placed in a constant temperature water bath, and the temperature is set to 30°C~40°C. Stirring is started. Tetrabutyl titanate is mixed with an equimolar amount of acetylacetone and stirred for 20min~40min to obtain a mixed solution. The mixed solution is then diluted with anhydrous ethanol to obtain solution A. Deionized water, anhydrous ethanol and catalyst are mixed to obtain solution B. Under continuous stirring, equal volumes of solution A and solution B are added dropwise to the NiO suspension at a constant rate. After the addition is complete, the reaction is stirred at a constant temperature for 4h~12h. Stirring is stopped and the mixture is allowed to stand for 12h~24h. The product is separated by centrifugation. The washed product is dried in a vacuum drying oven at 60°C~80°C for 6h~12h to obtain amorphous TiO2-coated NiO precursor powder. S23. Place the amorphous TiO2-coated NiO precursor powder in a muffle furnace, heat it to 400°C~600°C at a rate of 1°C / min~5°C / min, calcine for 2h~4h, cool and grind to obtain TiO2-coated NiO powder. Step 3: Heat-treat the TiO2-NiO-doped Co3S4 / CoS in a muffle furnace to obtain transition metal oxide / sulfide electrode material.

2. The method for preparing the transition metal oxide / sulfide electrode material as described in claim 1, characterized in that, In step one, the specific method for preparing the metal-organic framework material ZIF-67 using 2-methylimidazole and a cobalt source includes: dissolving 2-methylimidazole in methanol to obtain a clear and transparent solution A; dissolving the cobalt source in methanol to obtain solution B; stirring for more than 2 hours; mixing solution A and solution B; allowing the mixture to stand at 25°C for 12 to 36 hours; and then filtering, washing, and drying at 60°C to 90°C to obtain the metal-organic framework material ZIF-67.

3. The method for preparing the transition metal oxide / sulfide electrode material as described in claim 2, characterized in that, The cobalt source is cobalt nitrate hexahydrate; The ratio of 2-methylimidazole to methanol is 0.03 mol to 0.05 mol: 100 mL to 300 mL; the ratio of cobalt nitrate hexahydrate to methanol is 0.01 mol: 100 mL to 300 mL.

4. The method for preparing the transition metal oxide / sulfide electrode material as described in claim 1, characterized in that, The specific method of step two includes: adding metal-organic framework material ZIF-67, sulfur source and TiO2-coated NiO powder to ethanol, sonicating for 10 min to 20 min until fully dispersed to obtain a solution; placing the solution in a high-pressure reactor and reacting at 120℃ to 160℃ for 12 h to 48 h to obtain a black solution; The precipitate in the black solution was filtered onto a microporous membrane by vacuum filtration and washed multiple times with anhydrous ethanol. The microporous membrane was then placed in a vacuum drying oven at a temperature of 70℃~90℃ for 12h~36h to obtain TiO2-NiO Co3S4 / CoS.

5. The method for preparing the transition metal oxide / sulfide electrode material as described in claim 4, characterized in that, The sulfur source is thioacetamide or thiourea.

6. The method for preparing the transition metal oxide / sulfide electrode material as described in claim 4, characterized in that, The ratio of ethanol, metal-organic framework material ZIF-67, and sulfur source is 5 mL~7 mL: 10 mg~13 mg: 19 mg~20 mg.

7. The method for preparing the transition metal oxide / sulfide electrode material as described in claim 1, characterized in that, In step three, the heat treatment temperature is 400℃~500℃, the heating rate is 2℃ / min~4℃ / min, and the holding time is 1h~3h.

8. The method for preparing the transition metal oxide / sulfide electrode material as described in claim 1, characterized in that, In S21, the molar ratio of nickel nitrate to urea is 1:3~5, and the concentration of the nickel nitrate solution is 0.01M~0.2M; In S22, the ratio of NiO to anhydrous ethanol is 1g~10g:100mL~400mL; The mass ratio of NiO to tetrabutyl titanate is 1~10:20:100; In solution B, the catalyst is 0.2M nitric acid, and the ratio of deionized water, anhydrous ethanol and catalyst is 10mL~20mL:5mL~10mL:1mL~2mL.

9. A supercapacitor, characterized in that, The positive electrode of the supercapacitor is prepared from a transition metal oxide / sulfide electrode material, which is prepared by the method for preparing the transition metal oxide / sulfide electrode material according to any one of claims 1-8.

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