Mo2S3 / Ni3S2atNiWO4 / NF composite electrode material and preparation method thereof

Abstract

The invention relates to the technical field of supercapacitors, in particular to a Mo2S3 / Ni3S2-coated NiWO4 / NF composite electrode material and a preparation method thereof. The preparation of the Mo2S3 / Ni2S3-coated NiWO4 core-shell composite electrode and the research on the electrochemical performance of the Mo2S3 / Ni2S3-coated NiWO4 core-shell composite electrode are not reported yet. In order to solve the technical problems, the invention provides the Mo2S3 / Ni3S2-coated NiWO4 / NF composite electrode material, Mo2S3 / Ni3S2 disulphide is used as a core layer, NiWO4 is used as a shell layer, and a composite electrode with high conductivity, rapid reaction kinetics and excellent structural stability is constructed; the Mo2S3 / Ni3S2 bisulfide provides high specific capacity through a multi-oxidation-state reaction, meanwhile, the high conductivity of Ni3S2 accelerates electron transmission, a NiWO4 shell layer effectively buffers volume expansion / shrinkage of sulfide in the charging and discharging process, collapse of an electrode structure is inhibited, and the balance of high power density and long cycle life of the supercapacitor is facilitated.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of supercapacitors, in particular to a Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material and a preparation method thereof. BACKGROUND

[0002] As an important electrochemical energy storage device, supercapacitors have shown a broad application prospect in the fields of new energy vehicles, rail transit, and power storage, due to their fast charge-discharge characteristics, high power density, and long cycle life. However, the low energy density (usually only 1 / 10-1 / 5 of that of lithium-ion batteries) of supercapacitors seriously limits their practical application range. Studies have shown that the performance of electrode materials is the key factor determining the energy density of supercapacitors, and therefore, the development of electrode materials with high conductivity, high specific capacity, and excellent cycle stability has become the current research focus.

[0003] Transition metal sulfides (such as Ni3S2 and Mo2S3) are considered to be extremely potential electrode materials for supercapacitors due to their multi-oxidation state characteristics, low electronegativity, and high theoretical specific capacity. Such materials can realize high energy storage through fast Faraday pseudo-capacitive reactions, but their practical application still faces significant challenges: on the one hand, sulfides are prone to volume expansion / contraction during charge-discharge, leading to electrode structure pulverization and shedding; on the other hand, the reaction kinetics of single sulfide systems is slow, and the interface charge transfer resistance is large, making it difficult to simultaneously meet the requirements of high power density and long cycle life.

[0004] To solve the above problems, the design of core-shell structure composite electrode materials has become an important research direction. By coating a functional shell layer on the surface of active substances (core), volume changes can be effectively inhibited, charge transfer can be accelerated, and electrochemical stability can be improved. For example, NiWO4, as a tungstate material, has been widely studied as a shell material in core-shell structures due to its unique layered structure and good ion diffusion capacity. The MnCo2O4@NiWO4 core-shell nanowire array electrode reported in the literature (Journal of Colloid and Interface Science, 2019, 563:405-413) significantly improves the cycle stability of the electrode (the capacity retention rate reaches 96% after 5000 cycles) through the coating of the NiWO4 shell layer. However, existing researches are mostly focused on oxide-based core-shell systems, and there is still a blank in the report of sulfide / tungstate composite electrodes.

[0005] In particular, the formation of a core-shell structure of NiWO4 and Mo2S3 / Ni3S2 has the following technical advantages: first, the NiWO4 shell layer can buffer the volume change of sulfide in the charging and discharging process, and maintain the structural integrity of the electrode; second, the high ionic conductivity of NiWO4 can accelerate the interface charge transfer and improve the reaction kinetics; finally, the synergistic effect of multiple components is expected to further improve the specific capacity and energy density of the electrode through the complementarity of redox reactions. However, there is no public report on the preparation and electrochemical performance of Mo2S3 / Ni2S3@NiWO4 core-shell composite electrodes, which limits the development and application of high-performance sulfide-based electrode materials.

[0006] Based on this, the present application provides a Mo2S3 / Ni2S3@NiWO4 core-shell structure composite electrode material, which simultaneously solves the problems of slow kinetics and structural instability of sulfide electrodes through structural design, providing a new technical solution for the development of high-energy-density supercapacitors. SUMMARY

[0007] The existing problem is that there is no research report on the preparation and electrochemical performance of Mo2S3 / Ni2S3@NiWO4 core-shell composite electrodes. In view of the above technical problems, the present application provides a Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material, and its preparation method comprises the following steps:

[0008] (1) The NiMoO4 / NF precursor is immersed in a Na2S aqueous solution, and after high-pressure hydrothermal reaction, the obtained product is washed with deionized water and vacuum dried to obtain a Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material; the temperature of the high-pressure hydrothermal reaction is 110-130℃; (2) The aqueous solution containing Na2WO4 and NiCl2 is mixed uniformly with the aqueous solution containing C4H6N2, and then the Mo2S3 / Ni3S2 / NF electrode material is immersed in the above mixed solution, and after high-temperature hydrothermal reaction, the obtained product is sequentially washed with deionized water and ethanol, and then vacuum dried to obtain a Mo2S3 / Ni3S2@NiWO4 / NF electrode material. The temperature of the high-temperature hydrothermal reaction is 120-140℃.

[0009] Preferably, the preparation method of the NiMoO4 / NF precursor is as follows: (1) A bimetallic NiMo-MOF is grown on the surface of the pretreated NF by a hydrothermal method to obtain a NiMo-MOF / NF electrode material; the hydrothermal reaction temperature is 110-130℃.

[0010] (2) The NiMo-MOF / NF electrode material is placed in a nitrogen or other inert gas atmosphere for high-temperature calcination to obtain a NiMoO4 / NF precursor. The calcination temperature is 300-400 DEG C.

[0011] Preferably, the preparation method of the pretreated NF is as follows: The NF is cut to the required size, and then the NF is sequentially placed in dilute hydrochloric acid, acetone, anhydrous ethanol and deionized water for ultrasonic cleaning for at least 20 min, and after taking out, vacuum drying is performed to obtain the pretreated NF.

[0012] The present application has the following beneficial effects: The Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material and the supercapacitor provided by the present application realize the following remarkable technical effects through a unique core-shell structure design and a multi-step preparation process: (1) The Mo2S3 / Ni3S2 double sulfide is used as the core layer, and the NiWO4 is used as the shell layer to construct a composite electrode with high conductivity, fast reaction kinetics and excellent structural stability; the Mo2S3 / Ni3S2 double sulfide provides high specific capacity through multi-oxidation state reaction, and the high conductivity of the Ni3S2 accelerates electron transmission; the NiWO4 shell layer effectively buffers the volume expansion / contraction of the sulfide during the charging and discharging process, inhibits the powdering of the electrode structure, and at the same time, the layered structure of the NiWO4 promotes ion diffusion and improves reaction kinetics; the charge transfer resistance at the core-shell interface is significantly reduced, realizing the balance between high power density and long cycle life.

[0013] (2) The pseudo-capacitive reaction of the core layer double sulfide and the Faradic reaction of the shell layer NiWO4 synergistically contribute to a specific capacity of 1200 F g-1 at a current density of 1 A g-1, which is 2.5 times that of the Mo2S3 / NF electrode material and 1.5 times that of the Ni3S2 / NF electrode material. -1 -1 The above; the NiWO4 shell layer is designed through mechanical support and ion rapid transmission channel, and the capacity retention rate is more than 91 % after 3000 cycles, which is much better than that of a single sulfide system (usually less than 2000 cycles); (3) The NiMo-MOF precursor is in-situ grown on the pretreated NF surface through a hydrothermal method to ensure that the active substance is tightly combined with the substrate; high-temperature calcination is converted into NiMoO4, and then sulfidation treatment is performed to obtain the double sulfide core layer, and the process parameters (temperature 110-130 DEG C) are easy to control; the NiWO4 shell layer is coated through low-temperature (120-140 DEG C) hydrothermal method, which can avoid the destruction of the core layer structure; the hydrothermal method is used to replace the traditional high-temperature solid-phase method to reduce energy consumption; Na2S, Na2WO4 and other cheap raw materials are used to significantly reduce the preparation cost; (4) In the prior art, the sulfide electrode has a fast capacity attenuation due to volume change (such as MoS2, 50 % capacity attenuation after 1000 cycles); ​The capacity retention rate of the base electrode after 500 cycles is usually <80%), while the present invention uses NiW The dual functions of rigid support and flexible cushioning of the shell extend the cycle life to more than 3,000 times, solving the key bottleneck in the commercial application of sulfide electrodes. (5) The Mo2S3 / Ni3S2 prepared by the present invention using NiMo-MOF as a precursor retains the characteristics of large specific surface area and high porosity of the NiMo-MOF framework, providing more redox active sites for the Mo2S3 / Ni3S2 composite electrode material, which is very beneficial to further improving the electrochemical performance of the obtained Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material; (6) This invention uses core-shell structure innovation and process optimization to transform NiW into Shell and M / N The core-layer combination solves the problem of poor cycle stability of sulfide while maintaining its high specific capacity, providing a key material solution for the practical application of high energy density supercapacitors. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 These are SEM images of the electrode materials obtained in different steps of Example 1 of the present invention; among them, a and b are NiMo-MOF / NF electrode materials obtained in Example 1; c and d are Mo2S3 / Ni3S2 / NF electrode materials obtained in Example 1; e and f are Mo2S3 / Ni3S2@NiWO4 / NF composite electrode materials obtained in Example 1.

[0015] Figure 2 These are the XRD spectra of the electrode materials (NiMo-MOF / NF electrode material, NiMo-MOF powder, Mo2S3 / Ni3S2 / NF electrode material, Mo2S3 / Ni3S2@NiWO4 / NF electrode material) obtained in each step of Example 1 of the present invention.

[0016] Figure 3 CV curves of the Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material obtained in Example 1 at different scanning speeds.

[0017] Figure 4 This is the GCD curve of the Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material obtained in Example 1 at different current densities.

[0018] Figure 5 This is the EIS curve obtained after fitting the Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material obtained in Example 1.

[0019] Figure 6GCD comparison curves of the electrode materials obtained in Examples 1-4 respectively at a current density of 1 A g -1

[0020] Figure 7 GCD comparison curves of the electrode materials obtained in Examples 1 and Comparative Examples 1-5 respectively at a current density of 1 A g -1

[0021] Figure 8 GCD comparison curves of the electrode materials obtained in Examples 1 and Comparative Examples 6-8 respectively at a current density of 1 A g -1

[0022] Figure 9 Capacity retention rate diagrams of the composite electrode materials obtained in Examples 1-4 respectively after cyclic charging and discharging for 3000 times at a current density of 5 A g -1 DETAILED DESCRIPTION

[0023] The application will be described in detail below in conjunction with the examples. However, it should be understood that the following examples are only illustrative of the embodiments of the application, and are not a limitation on the scope of the application.

[0024] NF used in the following examples of the application was purchased from Tianjin Aivixing Chemical Technology Co., Ltd., and the model was 10x10x0.1 cm.

[0025] Example 1

[0026] A preparation method of a Mo2S3 / Ni3S2@NiWO4 composite electrode material is as follows: (1) The NF (length x width x thickness = 10 cm x 10 cm x 0.1 cm) was cut into a size of 1 cm x 3.5 cm, and then the NF was sequentially ultrasonically cleaned in a 3M hydrochloric acid aqueous solution, acetone, anhydrous ethanol and deionized water for 20 min, the ultrasonic frequency was 30 kHz, and after taking out, it was placed in a vacuum drying oven at 60°C for 12 h to obtain a pretreated NF; (2) 950.4 mg of NiCl2·6H2O (4 mmol) and 488 mg of Na2MoO4·2H2O (2 mmol) were added to 20 mL of deionized water and mixed uniformly to obtain a solution A, and then 985 mg of C4H6N2 was added to 40 mL of deionized water and ultrasonically dissolved to form a solution B, the solution B was added to the solution A, and stirred and mixed uniformly, and then the pretreated NF was added to the above mixed solution, and transferred to a 100 mL high-pressure reaction kettle, and hydrothermally reacted at 120°C for 12 h, after the reaction was completed, the reaction product was sequentially washed with ethanol and deionized water for 3 times, and then placed in a vacuum drying oven at 50°C for 12 h to obtain a NiMo-MOF / NF electrode material;​​​​ (3) The NiMo-MOF / NF electrode material was placed in a tube furnace, and heated to 350℃ at a rate of 2℃ / min under nitrogen atmosphere and kept for 2 h. After natural cooling to room temperature, the NiMoO4 / NF electrode material was obtained; (4) 0.72 g of Na2S·9H2O was added to 40 mL of deionized water and stirred to mix uniformly to obtain a Na2S aqueous solution. Then, the NiMoO4 / NF obtained in step (3) was added to the Na2S aqueous solution, and then transferred to a 100 mL high-pressure reaction kettle. The reaction was carried out at 120℃ for 2 h. After the reaction was completed, the obtained product was washed with deionized water for 3 times, and then placed in a vacuum drying box at 50℃ for drying for 12 h to obtain the Mo2S3 / Ni3S2 / NF electrode material; (5) 329.9 mg of Na2WO4·2H2O (1 mmol) and 237.7 mg of NiCl2·6H2O (1 mmol) were added to 30 mL of deionized water, and stirred for 30 min to mix uniformly to obtain an aqueous solution containing Na2WO4 and NiCl2. Then, the Mo2S3 / Ni3S2 / NF electrode material obtained in step (4) was added to the aqueous solution containing Na2WO4 and NiCl2, and then transferred to a 50 mL high-pressure reaction kettle. The reaction was carried out at 130℃ for 1 h. After the reaction was completed, the obtained product was washed with deionized water and ethanol for 3 times, respectively. Then, vacuum drying was carried out at 60℃ for 12 h to obtain the Mo2S3 / Ni3S2@NiWO4 / NF electrode material.

[0027] Example 2 was the same as Example 1, except that the amount of Na2S·9H2O used in Example 2 was 0.2 g.

[0028] Example 3 was the same as Example 1, except that the amount of Na2S·9H2O used in Example 3 was 0.35 g.

[0029] Example 4 was the same as Example 1, except that the amount of Na2S·9H2O used in Example 4 was 1.2 g.

[0030] Comparative Example 1 was the Mo2S3 / Ni3S2 / NF electrode material obtained in Example 1.

[0031] Comparative Example 2 is that 329.9 mg of Na2WO4·2H2O (1 mmol) and 237.7 mg of NiCl2·6H2O (1 mmol) are added to 30 mL of deionized water, stirred for 30 min, and then mixed uniformly to obtain an aqueous solution containing Na2WO4and NiCl2. Then, the pretreated NF is added to the aqueous solution containing Na2WO4and NiCl2, and then transferred to a 50 mL high-pressure reaction kettle. The reaction is carried out at 130°C for 1 h. After the reaction is completed, the product is washed with deionized water and ethanol for 3 times, respectively, and then vacuum dried at 60°C for 12 h to obtain the NiWO4 / NF electrode material.

[0032] Comparative Example 3 is the same as Example 1, except that the hydrothermal reaction time in step (4) is 1 h.

[0033] Comparative Example 4 is the same as Example 1, except that the hydrothermal reaction time in step (4) is 4 h.

[0034] Comparative Example 5 is the same as Example 1, except that the hydrothermal reaction time in step (4) is 10 h.

[0035] Comparative Example 6 is the same as Example 1, except that the amount of NiCl2·6H2O used in step (2) of Comparative Example 6 is 2 mmol, and the amount of Na2MoO4·2H2O used is 4 mmol.

[0036] Comparative Example 7 is the same as Example 1, except that the amount of NiCl2·6H2O used in step (2) of Comparative Example 7 is 3 mmol, and the amount of Na2MoO4·2H2O used is 3 mmol.

[0037] Comparative Example 8 is the same as Example 1, except that the preparation method in step (2) is as follows: 2 mmol of Ni(NO3)2·6H2O, 2 mmol of Na2MoO4·2H2O, 0.5 mmol of CO(NH2)2, and 1 mmol of NH4F are dissolved in 50 mL of deionized water to obtain a mixed solution. The pretreated NF and the above solution are transferred into a 100 mL PTFE high-pressure reaction kettle, and the reaction is carried out at 150°C for 6 h. After the reaction is completed, the product is washed with deionized water and ethanol for 3 times, respectively, and then vacuum dried. The hydrated nickel molybdenum oxide is formed in situ on the surface of the pretreated NF, which is recorded as NiMoO4·xH2O / NF electrode material.

[0038] Performance test

[0039] The three-electrode system was used to test the related performance of the electrodes obtained in the examples and the comparative examples. The electrodes obtained in the examples and the comparative examples were used as the working electrode of the three-electrode system, the platinum plate was used as the counter electrode, the Hg / HgO electrode was used as the reference electrode, the electrolyte was a 3 mol / L potassium hydroxide aqueous solution, and the electrochemical workstation was PGSTAT-302N from Switzerland. The working voltage range of the CV curve of the sample in the example and the comparative example was selected to be 0-0.6 V, the scanning rate was selected to be 5 mv, 10 mv, 20 mv, 30 mv, and 50 mv·s 1 , the current density of the GCD curve was selected to be 1 A, 2 A, 3 A, 5 A, and 10 A g -1 . The specific test results of the examples 1-4 and the comparative examples 1-5 at the current density of 1 A g -1 are shown in Table 1 and Table 1-1.

[0040] Table 1

[0041] Table 1-1

[0042] As shown in the drawings in the specification, Figure 1 (a), the NiMo-MOF obtained in the example 1 presents a plurality of uniformly arranged spherical shapes, and the size is about 100 nm. After the NiMo-MOF is sulfided, the surface of the sphere becomes rough, and the arrangement of Ni3S2 / Mo2S3 is more compact ( Figure 1 (b), Figure 1 In (c), NiWO4 presents a dense nanorod, which is uniformly coated on the surface of Ni3S2 / Mo2S3. The Mo2S3 / Ni3S2@NiWO4 heterostructure is beneficial to increase the reaction active site, improve the conductivity and structural stability of the electrode, and effectively relieve the volume expansion of the Ni3S2 / Mo2S3 electrode material in the cyclic charge and discharge process.

[0043] The drawings in the specification Figure 2 are XRD patterns of the materials obtained in different steps of the example 1. The XRD pattern of the NiMo-MOF shows that new diffraction peaks appear at 2θ = 33.76° and 59.8°, which are respectively attributed to the (62) and (782) crystal faces of the Ni-MOF, and the (111) and (222) crystal faces of the Mo-MOF are respectively attributed to the diffraction peaks at 9.06° and 27.08°. ​​The diffraction peaks of the crystal face are weakened, indicating that the Ni ions are successfully introduced and greatly change the self-assembly process of the MOFs, and the NiMo-MOF is successfully synthesized. After sulfidation of the NiMo-MOF, the characteristic peaks of the MOF disappear, and the diffraction peaks appearing at 21.56° and 35.22° correspond to the (002) and (012) crystal faces of Mo2S3 (PDF #40-0972), and the diffraction peaks appearing at 30.98°, 37.76°, 49.46° and 54.8° correspond to the (110), (003), (113) and (122) crystal faces of Ni3S2 (PDF # 44-1418), respectively, proving that the NiMo-MOF is successfully converted into the Mo2S3 / Ni3S2 composite electrode material. The compounding of NiWO4 does not cause changes in the diffraction peaks, indicating that it has low crystallinity and rich crystal defects, and these defects can provide additional active sites and promote ion diffusion. Compared with the diffraction peaks of the Mo2S3 / Ni3S2 / NF, the diffraction peaks are slightly shifted to the left after compounding the NiWO4, which may be caused by the lattice distortion caused by defects.

[0044] The description is accompanied by Figure 3 The CV curves of the Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material obtained in Example 1 at different scan rates are shown. The test results show that as the scan rate increases, the oxidation peak and the reduction peak shift to the positive potential and the negative potential, respectively, the anode peak current gradually increases, and the cathode peak current gradually decreases.

[0045] The description is accompanied by Figure 4 The GCD curves of the Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material obtained in Example 1 at different current densities are shown. In the potential window of 0-0.5 V, the GCD curves of the Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material at current densities of 1 A, 2 A, 3 A, 5 A and 10 A g -1 were measured, respectively, and the results show that the specific capacitance of the composite electrode material is 2324 F g -1 at 1 A g -1 , the GCD curve is close to symmetry, and a certain voltage platform appears, indicating good coulombic efficiency.

[0046] The Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material obtained in Example 1 was subjected to EIS test, and the Nyquist diagram is shown in Figure 5As shown in the figure. In the high-frequency region, the semicircle diameter corresponds to the interfacial charge transfer resistance (Rct). The Rct of Mo2S3 / Ni3S2@NiWO4 / NF is 2.513 Ω. The intersection with the x-axis represents the equivalent series resistance (Rs). The fitted Rs value is 0.597 Ω. In the low-frequency region, the straight line tends to the Y-axis. The smaller semicircle diameter and larger slope indicate that the composite electrode material has faster ion diffusion and electron transport capabilities.

[0047] Instructions attached Figure 6 The electrode materials obtained in Examples 1-4 were respectively -1 As shown in the figure, the charge and discharge duration of the Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material obtained in Example 1 is longer and has a larger specific capacitance. -1 When the specific capacitance of the electrode materials obtained in Examples 1-4 is 2324, 1256, 1670 and 1473 F g, respectively -1 , proving that sodium sulfide concentration has a significant effect on the specific capacitance of the electrode material. Example 1 has the best degree of sulfidation, which not only provides abundant reactive sites but also retains sufficient interlayer space, thus reducing the charge transfer resistance.

[0048] Instructions attached Figure 7 The electrode materials obtained in Example 1 and Comparative Examples 1-5 were respectively subjected to the conditions of a current density of 1 A g -1 As shown in the figure, the charge and discharge duration of the Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material obtained in Example 1 is longer and the specific capacitance is larger.

[0049] Instructions attached Figure 8 The electrode materials obtained in Example 1 and Comparative Examples 6-8 were respectively -1 The GCD comparison curve of the Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material obtained in Example 1 has a specific capacitance of 2324 F g -1 The specific capacitances of the composite electrode materials obtained in Comparative Examples 6, 7 and 8 were 1286 F g -1 、1455 F g -1 and 1140 F g -1 , proving that Example 1 has the best energy storage performance.

[0050] Instructions attached Figure 9 The cycle performance diagrams of the composite electrode materials obtained in Examples 1-4 as working electrodes in the three-electrode system are shown in the figure. As can be seen from the figure, at 5A g -1After 3000 charge-discharge cycles at a current density of 1 A / g, the Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material can still maintain 93.7% of the initial capacitance, the capacity retention rate of Example 2 is 73.1%, the capacity retention rate of Example 3 is 86.3%, and the capacity retention rate of Example 4 is 81.2%. It is proved that Example 1 can maintain excellent capacity value after long-term cycle, and therefore can be popularized and used as an electrode material in supercapacitors.

[0051] Based on the above ideal embodiments according to the application, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the application. The technical scope of the application is not limited to the content of the specification, and the technical scope must be determined according to the scope of claims.

Claims

1. A Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material, characterized in that: The preparation method comprises the following steps: (1) Sulfurizing the NiMoO4 / NF precursor through a hydrothermal reaction to obtain the Mo2S3 / Ni3S2 / NF electrode material; (2) NiWO4 was coated on the surface of Mo2S3 / Ni3S2 / NF electrode material through hydrothermal reaction to obtain Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material.

2. The Mo2S3 / Ni3S2@NiWO4NF composite electrode material according to claim 1, characterized in that: The preparation method of the NiMoO4 / NF precursor is as follows: (1) Bimetallic NiMo-MOF was grown on the surface of pretreated NF by hydrothermal method to obtain NiMo-MOF / NF electrode material; (2) The NiMo-MOF / NF electrode material is placed in a nitrogen or other inert gas atmosphere and calcined at high temperature to obtain a NiMoO4 / NF precursor.

3. The Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material according to claim 2, characterized in that: The preparation method of pretreated NF is as follows: The NFs were cut into the required size, and then ultrasonically cleaned in dilute hydrochloric acid, acetone, anhydrous ethanol and deionized water for at least 20 min respectively. After being taken out, they were vacuum dried to obtain the pretreated NFs.

4. The Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material according to claim 2, characterized in that: The hydrothermal reaction temperature in step (1) is 110-130°C.

5. The Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material according to claim 2, characterized in that: The calcination temperature in step (2) is 300-400°C.

6. The Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material according to claim 1, characterized in that: The method of step (1) is as follows: The NiMoO4 / NF precursor was immersed in a Na2S aqueous solution, and after a high-pressure hydrothermal reaction, the obtained product was washed with deionized water and vacuum dried to obtain the Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material.

7. The Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material according to claim 6, characterized in that: The temperature of the high-pressure hydrothermal reaction is 110-130°C.

8. The Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material according to claim 1, characterized in that: The method of step (2) is as follows: An aqueous solution containing Na2WO4 and NiCl2 is evenly mixed with an aqueous solution containing C4H6N2, and then the Mo2S3 / Ni3S2 / NF electrode material is immersed in the above mixed solution. After a high-temperature hydrothermal reaction, the obtained product is washed with deionized water and ethanol in turn, and vacuum dried to obtain the Mo2S3 / Ni3S2@NiWO4 / NF electrode material.

9. The Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material according to claim 8, characterized in that: The temperature of the high-temperature hydrothermal reaction is 120-140°C.

10. A supercapacitor, characterized in that: The Mo2S3 / Ni3S2@NiWO4 / NF composite electrode material obtained according to any one of claims 1 to 9 is used as the positive electrode material.

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