Co3S4 / WS2 composite material as well as preparation method and application thereof

Abstract

The invention relates to the field of new-generation energy materials, and provides a Co3S4 / WS2 composite material as well as a preparation method and application thereof. The preparation method comprises the following steps: dispersing cobalt acetate tetrahydrate and deionized water in N, N-dimethylformamide to obtain a solution A; terephthalic acid, deionized water and triethylamine are dispersed in N, N-dimethylformamide, and a solution B is obtained; mixing and stirring the solution A and the solution B to obtain a reaction product, and centrifuging, washing and drying the reaction product to obtain a Co-BDC precursor and the like, thereby obtaining the Co3S4 / WS2 composite material. WS2 is introduced into Co3S4 to construct a heterostructure, so that the electron mobility of the negative electrode material is improved, the conductivity and reaction kinetics are further enhanced, and the prepared Co3S4 / WS2 negative electrode material is high in specific capacity, has good rate capability and cycling stability and is particularly suitable for manufacturing a sodium ion battery negative electrode.

Description

Technical Field

[0001] The present invention relates to the technical field of a new generation of energy materials, and in particular to a Co3S4 / WS2 composite material and a preparation method and application thereof. Background Art

[0002] Fossil fuels are the most widely used energy source in the world today, but their widespread use has also led to resource shortages and environmental degradation. Consequently, renewable clean energy sources such as wind, tidal, and solar energy have been developed. The availability of both instantaneous and intermittent renewable energy has spurred the rapid development of large-scale energy storage systems. Rechargeable batteries are considered a viable strategy due to their flexibility, high energy conversion efficiency, and simplified maintenance. Lithium-ion batteries (LIBs) have an overwhelmingly dominant position in the power supply market for advanced consumer electronics and even electric vehicles, thanks to their high energy density, long lifespan, and low maintenance costs. However, the low abundance and uneven distribution of lithium make it difficult to meet the massively growing energy demand expected in the near future.

[0003] Inspired by the similar chemical properties of sodium and lithium, sodium-ion batteries (SIBs) have been widely studied and are considered to be the most promising commercial alternative power technology to lithium-ion batteries, especially for large-scale energy storage applications of intermittent and renewable energy sources and smart grids due to the low cost and natural abundance of sodium resources. Considerable efforts have been made to apply the successful experience of LIBs systems to SIBs, especially in electrode materials. Sodium is in the same group as lithium in the periodic table, has similar properties to lithium, has a redox potential close to that of lithium, and has more abundant crustal reserves (Na: 2.8wt%, Li: 0.0017wt%). It is worth mentioning that sodium-ion batteries (SIBs) were also studied in the early days of lithium-ion battery research. However, the larger ionic radius (Na + is 1.02 Å, Li + 0.76 Å) leads to sluggish reaction kinetics, which usually results in low capacity, poor rate capability, poor cycling stability, or even complete electrochemical inactivity, such as graphitic carbon, the most commonly used anode material in lithium-ion batteries. Therefore, the development of high-performance SIBs electrode materials remains an urgent need for their practical application.

[0004] Transition metal sulfides (TMSs) are a promising class of graphite-alternative energy storage materials due to their high specific capacitance, excellent rate capability, long cycle life, and low production cost. However, voltage hysteresis and volume expansion associated with structural changes still need to be addressed. Currently, TMSs based on iron, cobalt, nickel, molybdenum, and copper are being studied to improve sodium ion storage performance through strategies such as nanostructure design, composition adjustment, and composite conductive / protective materials.

[0005] Metal-Organic Frameworks (MOFs) and their derived nanomaterials, as a class of porous materials with special properties, have attracted widespread attention due to their high porosity, large specific surface area, unique morphology and adjustable chemical composition. In addition, the preparation of highly controllable carbon nanostructured materials using MOFs as templates has gradually become a research hotspot in recent years. Derived cobalt-based sulfide nanomaterials have been widely studied as sodium-ion battery anode materials due to their high theoretical capacity. However, when applying these materials to sodium-ion battery anodes, there are still many challenges, including relatively low electrical conductivity, slow kinetic reaction rate, significant volume expansion and the shuttling effect of polysulfides. In order to overcome these problems, researchers usually adopt nanosizing strategies, constructing bimetallic heterostructures and surface coating methods.

[0006] Compared with single-component metal sulfides, heterogeneous multicomponent metal sulfides have obvious advantages. For example, heterojunctions with large lattice mismatches, distortions, and defects can greatly affect the behavior of charge carrier transport. At the same time, different coupling components can greatly promote interfacial reaction kinetics and accelerate electron / ion transport through the internal electric field on the heterojunction. In addition, the synergistic effect of different components will effectively avoid the aggregation of generated products and reduce the pressure of sodium ions during the insertion / extraction process. Therefore, it is necessary to construct heterojunctions to greatly improve the sodium storage electrochemical performance of the material. Summary of the Invention

[0007] In order to solve the above problems, the present invention provides a Co3S4 / WS2 composite material and its preparation method and application. The preparation method provided by the present invention is simple and convenient to operate and has low cost; the Co3S4 / WS2 composite material has low cost and excellent performance; the Co3S4 / WS2 composite material is used to prepare sodium ion batteries, which have high specific capacity, fast charge and discharge speed, and long cycle life.

[0008] In order to achieve the above object, the present invention provides the following technical solutions: The present invention provides a method for preparing a Co3S4 / WS2 composite material, comprising the following steps: 1) Dispersing cobalt acetate tetrahydrate and deionized water in N,N-dimethylformamide to obtain solution A; Dispersing terephthalic acid, deionized water, and triethylamine in N,N-dimethylformamide to obtain solution B; Mixing and stirring the solution A and the solution B to obtain a reaction product, and centrifuging, washing, and drying the reaction product to obtain a Co-BDC precursor; 2) carbonizing the Co-BDC precursor obtained in step 1) under a nitrogen atmosphere to obtain a Co@C precursor; 3) dispersing the Co@C precursor obtained in step 2), sodium tungstate dihydrate, and thioacetamide in deionized water and ultrasonically treating the mixture to obtain a mixed solution; 4) subjecting the mixed solution obtained in step 3) to a hydrothermal reaction to obtain a reaction product, and centrifuging, washing, and drying the reaction product to obtain a Co3S4 / WS2 composite material.

[0009] Preferably, in step 1), the ratio of the mass of cobalt acetate tetrahydrate to the volume of deionized water and N,N-dimethylformamide is 964 mg: 1-3 ml: 25 ml; The volume ratio of the mass of terephthalic acid to the volume of deionized water, the volume of triethylamine, and the volume of N,N-dimethylformamide is 250 mg: 1-3 ml: 1-3 ml: 20 ml.

[0010] Preferably, the mixing method in step 1) includes stirring, and the stirring time is 1 to 3 hours; The centrifugal conditions include: a rotation speed of 8000 rpm and a time of 2 min; Wash with anhydrous ethanol; The drying conditions include: temperature of 60° C. and time of 12 hours.

[0011] Preferably, the carbonization treatment conditions in step 2) include: a temperature of 500-600° C. and a time of 2 h.

[0012] Preferably, in step 3), the volume ratio of the mass of the Co@C precursor, the mass of sodium tungstate dihydrate, the mass of thioacetamide and deionized water is 30 mg: 150-180 mg: 150-200 mg: 60 ml; The ultrasonic treatment time is 30 min.

[0013] Preferably, the conditions for the hydrothermal reaction in step 4) include: a temperature of 180-200° C. and a time of 10-20 h.

[0014] Preferably, the centrifugal conditions in step 4) include: a rotation speed of 8000 rpm and a time of 2 min; Wash with anhydrous ethanol; The drying conditions include: temperature of 60° C. and time of 12 hours.

[0015] The present invention also provides a Co3S4 / WS2 composite material prepared by the preparation method described in the above technical solution.

[0016] The present invention also provides the use of the Co3S4 / WS2 composite material described in the above technical solution in preparing the negative electrode of a sodium ion battery.

[0017] Preferably, the components of the sodium ion battery include the Co3S4 / WS2 composite material, Ketjen black and polyvinyl difluoride; The mass ratio of the Co3S4 / WS2 composite material, Ketjen black and polyvinylidene fluoride is 7:2:1.

[0018] The present invention constructs a Co-based metal-organic nanomaterial and obtains a carbon skeleton with controllable morphology through high-temperature carbonization. By constructing a Co3S4 / WS2 bimetallic heterostructure on a carbon substrate, the problems of large volume expansion and poor cycle stability of transition metal sulfides are solved to obtain a new sodium ion battery negative electrode material with long cycle life and high specific capacity, providing feasible ideas and methods for exploring new energy storage electrode materials.

[0019] In the present invention, bimetallic sulfides derived from the carbonization of Co-BDC are first selected as the negative electrode material. This type of material has a high specific capacity, and the derived carbon material has a nanoscale structure, rich heteroatom doping and ideal conductivity. Transition metal cobalt and tungsten are selected from the metal sulfides. Because cobalt tetrasulfide derived from Co-BDC has a high theoretical capacity, WS2 heterostructure is introduced on Co3S4 to reduce the resistance of sodium ions to embedding / de-embedding in the positive and negative electrodes, improve the electron mobility of the negative electrode material, and thus improve the sodium storage reaction kinetics of the obtained sample.

[0020] Beneficial effects of the present invention: The present invention introduces WS2 into Co3S4 to construct a heterostructure, thereby improving the electron mobility of the negative electrode material, thereby enhancing the conductivity and reaction kinetics. The prepared Co3S4 / WS2 negative electrode material has high specific capacity, good rate performance and cycle stability, and is particularly suitable for manufacturing sodium ion battery negative electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below.

[0022] Figure 1 This is a field emission scanning electron microscope (SEM) image of the Co-BDC precursor prepared in Example 1; Figure 2 This is a field emission scanning electron microscope (SEM) image of the Co3S4 / WS2 composite material prepared in Example 1; Figure 3 The Co3S4 / WS2 electrode material prepared in Example 1 is used as the negative electrode material for sodium ion batteries at 2 A g -1 Cycling performance diagram of 100 cycles under different current densities; Figure 4The Co3S4 / WS2 composite material prepared in Example 1 was used as the negative electrode material for sodium ion batteries at 2 A g -1 Cycling performance diagram of 200 cycles at the same current density. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing a Co3S4 / WS2 composite material, comprising the following steps: 1) Dispersing cobalt acetate tetrahydrate and deionized water in N,N-dimethylformamide to obtain solution A; Dispersing terephthalic acid, deionized water, and triethylamine in N,N-dimethylformamide to obtain solution B; Mixing and stirring the solution A and the solution B to obtain a reaction product, and centrifuging, washing, and drying the reaction product to obtain a Co-BDC precursor; 2) carbonizing the Co-BDC precursor obtained in step 1) under a nitrogen atmosphere to obtain a Co@C precursor; 3) dispersing the Co@C precursor obtained in step 2), sodium tungstate dihydrate, and thioacetamide in deionized water and ultrasonically treating the mixture to obtain a mixed solution; 4) subjecting the mixed solution obtained in step 3) to a hydrothermal reaction to obtain a reaction product, and centrifuging, washing, and drying the reaction product to obtain a Co3S4 / WS2 composite material.

[0024] The present invention disperses cobalt acetate tetrahydrate and deionized water in N,N-dimethylformamide to obtain solution A; disperses terephthalic acid, deionized water, and triethylamine in N,N-dimethylformamide to obtain solution B; mixes and stirs solution A and solution B to obtain a reaction product, which is then centrifuged, washed, and dried to obtain a Co-BDC precursor. In the present invention, the volume ratio of cobalt acetate tetrahydrate to deionized water and DMF is preferably 964 mg:1-3 ml:25 ml, more preferably 964 mg:3 ml:25 ml. In the present invention, the volume ratio of terephthalic acid to deionized water and triethylamine to N,N-dimethylformamide is 250 mg:1-3 ml:1-3 ml:20 ml, more preferably 250 mg:3 ml:2 ml:20 ml. In the present invention, the stirring time is preferably 1-3 hours. In the present invention, the centrifugation conditions preferably include: a rotation speed of 8000 rpm and a time of 2 minutes. In the present invention, anhydrous ethanol is preferably used for washing. In the present invention, the drying conditions preferably include: a temperature of 60° C. and a time of 12 hours.

[0025] The obtained Co-BDC precursor is carbonized under a nitrogen atmosphere to obtain a Co@C precursor. In the present invention, the carbonization treatment conditions preferably include: a temperature of 500-600° C. and a time of 2 hours.

[0026] The present invention disperses the obtained Co@C precursor, sodium tungstate dihydrate, and thioacetamide in deionized water and ultrasonically treats the mixture to obtain a mixed solution. In the present invention, the volume ratio of the Co@C precursor, the mass of sodium tungstate dihydrate, the mass of thioacetamide, and deionized water is preferably 30 mg:150-180 mg:150-200 mg:60 ml, more preferably 30 mg:165 mg:150 mg:60 ml. In the present invention, the ultrasonic time is preferably 30 min.

[0027] The mixed solution obtained in the present invention is subjected to a hydrothermal reaction to obtain a reaction product, which is then centrifuged, washed, and dried to obtain a Co3S4 / WS2 composite material. In the present invention, the hydrothermal reaction conditions preferably include: a temperature of 180-200°C and a time of 10-20 hours. In the present invention, the centrifugation conditions preferably include: a speed of 8000 rpm and a time of 2 minutes. In the present invention, anhydrous ethanol is preferably used for washing. In the present invention, the drying conditions preferably include: a temperature of 60°C and a time of 12 hours.

[0028] The present invention also provides a Co3S4 / WS2 composite material prepared by the preparation method described in the above technical solution.

[0029] The present invention also provides the use of the Co3S4 / WS2 composite material described in the above technical solution in preparing a negative electrode for a sodium ion battery. In the present invention, the components of the sodium ion battery preferably include the Co3S4 / WS2 composite material, Ketjen black, and polyvinyl difluoride. In the present invention, the mass ratio of the Co3S4 / WS2 composite material, Ketjen black, and polyvinyl difluoride is preferably 7:2:1. The present invention does not specifically limit the sources of the Ketjen black and polyvinyl difluoride; commercially available products conventionally used in preparing sodium ion batteries can be used.

[0030] In order to further illustrate the present invention, the present invention is described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0031] Example 1: A method for preparing a Co3S4 / WS2 composite material, comprising the following steps: 1. Dissolve 964 mg of cobalt acetate tetrahydrate and 3 ml of deionized water in 25 ml of N,N-dimethylformamide (DMF) as Solution A. Dissolve 250 mg of terephthalic acid, 3 ml of deionized water, and 2 ml of triethylamine in 20 ml of DMF as Solution B. Pour Solution A into Solution B and stir at room temperature for 3 hours to obtain a purple solution. Centrifuge the purple solution at 8000 rpm for 2 minutes and wash with anhydrous ethanol. Dry the resulting precipitate in a forced-air drying oven at 60°C for 12 hours to obtain Co-BDC powder. 2. 300 mg of the prepared Co-BDC powder was placed in a crucible and carbonized at 600 °C for 2 h in a tube furnace in a N2 atmosphere to obtain a Co@C precursor. 3. Then, 30 mg of the obtained Co@C precursor, 165 mg of sodium tungstate dihydrate, and 150 mg of thioacetamide were dispersed in 60 ml of deionized water and ultrasonicated for 0.5 h to obtain a mixed solution; 4. Finally, the mixed solution was transferred to a 100 ml polytetrafluoroethylene-lined sealed autoclave and reacted at 200°C for 20 h. After cooling to room temperature, the solvent thermal product was washed several times with anhydrous ethanol and then dried in a forced air drying oven at 60°C for 12 h to obtain a Co3S4 / WS2 composite material. The prepared Co3S4 / WS2 battery anode material, Ketjen Black, and polyvinyl difluoride (PVDF) were mixed in an N-methyl-2-pyrrolidone (NMP) solvent at a mass ratio of 7:2:1. The resulting slurry was then applied to a copper foil current collector and dried overnight in a vacuum oven at 120°C. After cooling to room temperature, the slurry was removed, sliced, and weighed. After equilibration in a glove box for 8 hours, the slurry was assembled into a sodium-ion battery and its electrochemical performance was tested.

[0032] Example 2: A method for preparing a Co3S4 / WS2 composite material, comprising the following steps: 1. Dissolve 964 mg of cobalt acetate tetrahydrate and 1 ml of deionized water in 25 ml of DMF (Solution A). Dissolve 250 mg of terephthalic acid, 1 ml of deionized water, and 1 ml of triethylamine in 20 ml of DMF (Solution B). Pour Solution A into Solution B and stir at room temperature for 1 hour to obtain a purple solution. Centrifuge the purple solution at 8000 rpm for 2 minutes and wash with anhydrous ethanol. Dry the resulting precipitate in a forced-air drying oven at 60°C for 12 hours to obtain Co-BDC powder. 2. 300 mg of the prepared Co-BDC powder was placed in a crucible and carbonized at 500 °C for 2 h in a tube furnace in a N2 atmosphere to obtain a Co@C precursor. 3. Then, 30 mg of the obtained Co@C precursor, 180 mg of sodium tungstate dihydrate, and 200 mg of thioacetamide were dispersed in 60 ml of deionized water and ultrasonicated for 0.5 h to obtain a mixed solution; 4. Finally, the mixed solution was transferred to a 100 ml polytetrafluoroethylene-lined sealed autoclave and reacted at 180°C for 10 h. After cooling to room temperature, the solvent thermal product was washed several times with anhydrous ethanol and then dried in a forced air drying oven at 60°C for 12 h to obtain a Co3S4 / WS2 composite material. The prepared Co3S4 / WS2 battery anode material, Ketjen Black, and polyvinyl difluoride (PVDF) were mixed in an N-methyl-2-pyrrolidone (NMP) solvent at a mass ratio of 7:2:1. The resulting slurry was then applied to a copper foil current collector and dried overnight in a vacuum oven at 120°C. After cooling to room temperature, the slurry was removed, sliced, and weighed. After equilibration in a glove box for 8 hours, the slurry was assembled into a sodium-ion battery and its electrochemical performance was tested.

[0033] Example 3: A method for preparing a Co3S4 / WS2 composite material, comprising the following steps: 1. Dissolve 964 mg of cobalt acetate tetrahydrate and 2 ml of deionized water in 25 ml of DMF (Solution A). Dissolve 250 mg of terephthalic acid, 1 ml of deionized water, and 3 ml of triethylamine in 20 ml of DMF (Solution B). Pour Solution A into Solution B and stir at room temperature for 1 hour to obtain a purple solution. Centrifuge the purple solution at 8000 rpm for 2 minutes and wash with anhydrous ethanol. Dry the resulting precipitate in a forced-air drying oven at 60°C for 12 hours to obtain Co-BDC powder. 2. 300 mg of the prepared Co-BDC powder was placed in a crucible and carbonized at 550 °C for 2 h in a tube furnace in a N2 atmosphere to obtain a Co@C precursor; 3. Then, 30 mg of the obtained Co@C precursor, 150 mg of sodium tungstate dihydrate, and 200 mg of thioacetamide were dispersed in 60 ml of deionized water and ultrasonicated for 0.5 h to obtain a mixed solution; 4. Finally, the mixed solution was transferred to a 100 ml polytetrafluoroethylene-lined sealed autoclave and reacted at 190°C for 15 h. After cooling to room temperature, the solvent thermal product was washed several times with anhydrous ethanol and then dried in a forced air drying oven at 60°C for 12 h to obtain a Co3S4 / WS2 composite material. The prepared Co3S4 / WS2 battery anode material, Ketjen Black, and polyvinyl difluoride (PVDF) were mixed in an N-methyl-2-pyrrolidone (NMP) solvent at a mass ratio of 7:2:1. The resulting slurry was then applied to a copper foil current collector and dried overnight in a vacuum oven at 120°C. After cooling to room temperature, the slurry was removed, sliced, and weighed. After equilibration in a glove box for 8 hours, the slurry was assembled into a sodium-ion battery and its electrochemical performance was tested.

[0034] The three Co3S4 / WS2 battery negative electrode materials prepared in Example 1 (denoted as a), 2 (denoted as b), and 3 (denoted as c) were measured at 2A g -1 Table 1 shows the characterization results of the Co3S4 / WS2 battery negative electrode materials prepared by Examples 1, 2, and 3. As shown in Table 1, the Co3S4 / WS2 battery negative electrode materials (a), (b), and (c) obtained by the preparation method of the present invention have a high electrochemical performance at 2A g -1 The battery still shows 764.321 mAh g after 100 cycles at high current density. -1 、327.235mAh g -1 、730.163 mAh g -1 Excellent sodium storage performance.

[0035] like Figure 2 From the field emission scanning electron microscope photograph of the Co3S4 / WS2 battery negative electrode material prepared in Example 1, it can be seen that its morphology is irregular spherical.

[0036] like Figure 3 The Co3S4 / WS2 composite material prepared in Example 1 was used as the negative electrode material for sodium ion batteries at 2 A g -1 Cycling performance diagram after 100 cycles at different current densities.

[0037] like Figure 4 The Co3S4 / WS2 composite material prepared in Example 1 was used as the negative electrode material for sodium ion batteries at 2 A g -1 The cycle performance diagram of 200 cycles under the current density is shown in Figure 2. Figure 4 It can be concluded that the 103rd cycle (specific capacity 747.314 mAh g -1 ) and then began to fluctuate and decay continuously. At about 200 cycles, the specific capacity was 573.783 mAh g -1 .

[0038] Table 1 Characterization results of Co3S4 / WS2 battery anode materials

[0039] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a Co3S4 / WS2 composite material, characterized in that: The following steps are involved: 1) dispersing cobalt acetate tetrahydrate and deionized water in N,N-dimethylformamide to obtain solution A; Dispersing terephthalic acid, deionized water and triethylamine in N,N-dimethylformamide to obtain solution B; The solution A and the solution B are mixed and stirred to obtain a reaction product, and the reaction product is centrifuged, washed and dried to obtain a Co-BDC precursor; 2) carbonizing the Co-BDC precursor obtained in step 1) under a nitrogen atmosphere to obtain a Co@C precursor; 3) dispersing the Co@C precursor obtained in step 2) with sodium tungstate dihydrate and thioacetamide in deionized water and subjecting them to ultrasonic treatment to obtain a mixed solution; 4) subjecting the mixed solution obtained in step 3) to a hydrothermal reaction to obtain a reaction product, and centrifuging, washing and drying the reaction product to obtain a Co3S4 / WS2 composite material.

2. The preparation method according to claim 1, characterized in that: In the step 1), the mass of cobalt acetate tetrahydrate, the volume of deionized water, and the volume ratio of N,N-dimethylformamide are 964 mg: 1-3 ml: 25 ml; The volume ratio of the mass of terephthalic acid to the volume of deionized water, the volume of triethylamine, and the volume of N,N-dimethylformamide is 250mg:1~3ml:1~3ml:20ml.

3. The preparation method according to claim 1, characterized in that: The mixing method of step 1) includes stirring, and the stirring time is 1 to 3 hours; The centrifugal conditions include: a rotation speed of 8000 rpm and a time of 2 min; Wash with anhydrous ethanol; The drying conditions include: temperature of 60° C. and time of 12 h.

4. The preparation method according to claim 1, characterized in that: The carbonization treatment conditions in step 2) include: a temperature of 500-600° C. and a time of 2 hours.

5. The preparation method according to claim 1, characterized in that: In the step 3), the mass of the Co@C precursor, the mass of the sodium tungstate dihydrate, the mass of thioacetamide and the volume ratio of deionized water are 30 mg: 150-180 mg: 150-200 mg: 60 ml; The ultrasonic treatment time is 30 min.

6. The preparation method according to claim 1, characterized in that: The conditions of the hydrothermal reaction in step 4) include: temperature of 180-200° C. and time of 10-20 h.

7. The preparation method according to claim 1, characterized in that: The centrifugal conditions in step 4) include: a rotation speed of 8000 rpm and a time of 2 min; Wash with anhydrous ethanol; The drying conditions include: temperature of 60° C. and time of 12 h.

8. A Co3S4 / WS2 composite material prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the Co3S4 / WS2 composite material according to claim 8 in preparing the negative electrode of a sodium ion battery.

10. The use according to claim 9, characterized in that: The components of the sodium ion battery include the Co3S4 / WS2 composite material, Ketjen black and polyvinylidene fluoride; The mass ratio of the Co3S4 / WS2 composite material, Ketjen black and polyvinylidene fluoride is 7:2:1.

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