Preparation method and application of cobalt selenide heterostructure lithium-sulfur battery composite material with hollow reticular spherical structure

Abstract

The invention discloses a preparation method and application of a cobalt selenide heterostructure Co-CoSe C lithium-sulfur battery composite material with a hollow reticular spherical structure, and belongs to the technical field of electrode materials. The material takes a hollow carbon sphere as a main body, and a Co-CoSe-C heterostructure is formed inside the hollow carbon sphere. The preparation method comprises the following steps: dispersing a cobalt source into carbon spheres by an excessive impregnation method, and loading heterostructure particles on carbon nanotubes grown in the carbon spheres by a vapor deposition method to obtain the hollow reticular spherical Co-CoSe-C heterojunction host. The method is short in process, simple in process and good in repeatability. Due to the unique staggered network structure of the obtained material, an additional active material can be anchored to the carbon nano tube in the shell layer, the contact area between a catalytic host and an active substance is increased, the size of the active substance in a sphere is reduced, and the chemical adsorption capacity and catalytic activity to polysulfide are remarkably improved; the shuttle effect is effectively relieved; and the reaction kinetics of the lithium-sulfur battery is improved.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method and application of a hollow reticular spherical structure Co-CoSe@C heterostructure lithium-sulfur battery composite material, and belongs to the technical field of preparation of lithium-sulfur battery positive electrode materials. BACKGROUND

[0002] Lithium-sulfur batteries (LSB) as the next generation of electrochemical energy storage systems have attracted extensive attention due to high specific capacity (1675 mAh g -1 ), energy density (2600 Wh Kg -1 ), low cost and environmental friendliness. However, lithium sulfide produced in the battery discharge process has intrinsic insulating properties, a shuttle effect of polysulfides and a large volume change in the process of multi-phase reversible conversion, which together cause slow reaction kinetics of the LSB and limit the application of lithium-sulfur batteries. Traditional spherical catalytic hosts have the characteristics of rich sulfur storage space and high conductivity, but from a macroscopic point of view, the catalytic conversion process of the polysulfides is a kind of face-to-face contact, and the effective active sites provided are limited. Therefore, how to improve the contact area between the catalytic host and the active material sulfur and increase the effective catalytic sites of the sulfur electrochemical process is the key to promoting the catalytic conversion of polysulfides. Here, a Co-CoSe@C heterostructure with a hollow reticular spherical structure is developed by an excess impregnation combined with a gas deposition method. Due to the unique design of the inner tube of the spherical structure, the high specific surface area of the carbon nanotube is characterized, the size of the active material in the conductive carbon sphere is effectively reduced under the condition of ensuring sulfur loading. This kind of spherical inner reticular structure can disperse the heterostructure in the ball, can disperse and anchor the active material to form a high-density active site. This increases the effective contact area with the catalytic site and improves the catalytic efficiency, which is of great significance for inhibiting the shuttle effect, promoting the catalytic conversion of polysulfides and improving the electrochemical properties of lithium-sulfur batteries. SUMMARY

[0003] Invention objectives

[0004] The application provides a preparation method and application of a sulfur-loaded Co-CoSe@C heterostructure lithium-sulfur battery composite material with a hollow reticular spherical structure. The heterojunction composite material prepared by the method has the characteristics of a highly dispersed hollow reticular spherical structure, can effectively provide more adsorption sites for polysulfides, accelerate the nucleation of Li2S, promote the diffusion and catalysis of LiPS / Li2S on the surface of the catalytic host material, reduce the diffusion energy barrier and activation energy of Li2S nucleation and dissolution, accelerate the redox kinetics of Li2S and improve the electrochemical performance of lithium-sulfur batteries, such as specific capacity, rate performance and cycle stability. The preparation method of the Co-CoSe@C heterostructure lithium-sulfur battery composite material with a hollow reticular spherical structure is simple in process and good in repeatability.

[0005] Solution

[0006] The first aspect of the present application provides a Co-CoSe@C heterostructure composite material of a sulfur-loaded hollow reticular spherical structure for a lithium-sulfur battery, characterized in that the composite material comprises a hollow reticular spherical structure of "carbon sphere-carbon nanotube", the carbon nanotube is on the surface or inside the carbon sphere, the Co-CoSe is uniformly distributed in the hollow carbon sphere material and the carbon nanotube inside the sphere, and sulfur is loaded on the Co-CoSe@C heterostructure composite material of the hollow reticular spherical structure.

[0007] The content of carbon in the composite material is 85% to 98%, the content of Co is 1% to 10%, the content of Se is 1% to 10%, and the content of sulfur is 65% to 80%.

[0008] Preferably, the content of carbon in the composite material is 90% to 95%, the content of Co is 1% to 5%, the content of Se is 1% to 3%, and the content of sulfur is 68% to 75%.

[0009] The inner diameter of the hollow carbon sphere cavity is 200 to 300 nm, and the carbon layer thickness is 15 to 35 nm.

[0010] The second aspect of the present application provides a preparation method of a Co-CoSe@C heterostructure composite material of a sulfur-loaded hollow reticular spherical structure for a lithium-sulfur battery, characterized in that it comprises the following steps:

[0011] Step 1, preparing a phenolic resin precursor powder;

[0012] Step 2, obtaining a carbon sphere with a silica template after high-temperature carbonization of the precursor powder obtained through step 1;

[0013] Step 3, obtaining a hollow carbon sphere after acid washing etching and drying of the carbon sphere obtained in step 2;

[0014] Step 4, dispersing the hollow carbon sphere obtained in step 3 in a solution containing cobalt, stirring, oil bath evaporation, and high-temperature pyrolysis to obtain a precursor powder containing cobalt comprising a "carbon sphere-carbon nanotube" hollow reticular spherical structure;

[0015] Step 5, obtaining a Co-CoSe@C heterostructure material comprising a "carbon sphere-carbon nanotube" hollow reticular spherical structure after gas phase deposition of selenium of the precursor powder containing cobalt comprising a "carbon sphere-carbon nanotube" hollow reticular spherical structure obtained in step 4;

[0016] Step 6: obtaining the sulfur-loaded Co-CoSe@C heterostructure lithium-sulfur battery composite material comprising the hollow reticular spherical structure of the "carbon sphere-carbon nanotube" by a liquid phase method through the Co-CoSe@C heterostructure material comprising the hollow reticular spherical structure of the "carbon sphere-carbon nanotube" obtained in step 5 and elemental sulfur.

[0017] The step 1 specifically comprises weighing raw materials, stirring, drying and grinding to obtain phenolic resin precursor powder.

[0018] The raw materials specifically comprise 100-200 mL of deionized water, 600-800 mL of anhydrous ethanol, 30-70 mL of ammonia water, 20-40 mL of tetraethyl orthosilicate, 3-8 g of resorcinol and 4-7 mL of formaldehyde.

[0019] The stirring time is 20-30 h; and the drying temperature is 65-75 DEG C.

[0020] The high-temperature carbonization process in the step 2 is to heat the precursor powder obtained in step 1 to 700-900 DEG C, and keep the temperature for 5 h to obtain the carbon sphere with silica as a template.

[0021] The acid washing etching process in the step 3 is to place the carbon sphere obtained in step 2 in a hydrofluoric acid solution with a concentration of 30%, keep for 40-56 h, wash until the solution is neutral, and vacuum dry.

[0022] The step 4 is to weigh 150-250 mg of the hollow carbon sphere obtained in step 3, disperse in 100-150 mL of a solution containing cobalt, stir, oil bath evaporate, high-temperature pyrolysis to obtain the precursor powder containing cobalt with the hollow reticular spherical structure of the "carbon sphere-carbon nanotube".

[0023] The solution containing cobalt specifically comprises cobalt nitrate hexahydrate, dicyandiamide and deionized water as a solvent; the cobalt nitrate hexahydrate is 0.5-2 mmol, and the dicyandiamide is 1-4 mmol.

[0024] The oil bath evaporation temperature is 110-140 DEG C; and the high-temperature pyrolysis specifically comprises heating the sample after oil bath evaporation to 700-900 DEG C, and keeping the temperature for 3-5 h.

[0025] The process of the selenium vapor deposition in the step 5 is to heat the precursor powder obtained in step 4 and selenium powder to 500-700 DEG C at the same time, keep the temperature for 1.5-3 h to obtain the Co-CoSe@C heterostructure material with the hollow reticular spherical structure of the "carbon sphere-carbon nanotube"; and the mass ratio of the precursor powder to the selenium powder is 1:0.5-0.8.

[0026] The step 6 disperses 80-150 mg of the Co-CoSe@C heterostructure material of the hollow reticular spherical structure of the "carbon sphere-carbon nanotube" obtained in step 5 into 350-500 mg of elemental sulfur in 15-30 mL of a mixed solution of carbon bisulfide and 5-15 mL of N-methylpyrrolidone, evaporates the solvent in an oil bath at 70 DEG C, and finally obtains the Co-CoSe@C heterostructure composite material of the hollow reticular spherical structure of the "carbon sphere-carbon nanotube" after sulfur loading by keeping at 200 DEG C for 30 min in an argon atmosphere.

[0027] The third aspect of the present application also provides an application of the Co-CoSe@C heterostructure lithium-sulfur battery positive electrode material of the hollow reticular spherical structure. The Co-CoSe@C heterostructure lithium-sulfur battery composite material of the hollow reticular spherical structure is obtained by mixing the Co-CoSe@C heterostructure composite material after sulfur loading, conductive carbon black and polyvinylidene fluoride according to a ratio of 7:2:1, using an electrode coating method, drying in a vacuum drying box at 60 DEG C for 24 h, cutting into a round piece, weighing, and then assembling a button cell.

[0028] The fourth aspect of the present application also provides a lithium-sulfur battery comprising the lithium-sulfur battery positive electrode material described above.

[0029] Beneficial effects

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] (1) The present application obtains the Co-CoSe@C heterostructure composite material with a hollow reticular spherical structure by adding cobalt nitrate hexahydrate, dicyandiamide and hollow carbon spheres into deionized water, stirring at room temperature and gas phase deposition. Compared with the traditional spherical catalytic host material, the present application has a short preparation process, simple process and good experimental repeatability. It is worth noting that the cobalt nanoparticles will promote part of the carbon atoms in the carbon sphere to arrange in a tubular structure at high temperature, and "grow" carbon nanotubes from the surface or inside of the carbon sphere, and finally form a hollow reticular spherical structure of "carbon sphere-carbon nanotube". The prepared hollow reticular spherical Co-CoSe@C heterostructure is helpful to anchor the additional active material to the carbon nanotubes in the shell layer, thereby enhancing the contact area between the catalytic host and the active material, reducing the size of the active material in the sphere, improving the chemical adsorption capacity of polysulfides and catalytic activity, effectively relieving the shuttle effect and improving the reaction kinetics of lithium-sulfur batteries.

[0032] The hollow carbon sphere synthesized by the hard template method has a smooth surface and a uniform thickness of the spherical shape, and the diameter is about 250nm, which is used as a host material for lithium-sulfur battery positive electrode and exhibits outstanding electrochemical performance, such as high specific capacity, rate performance and good cycle stability. At 0.1C, the initial specific capacity of the lithium bowl battery is as high as 1059.29mAh g -1 ; at 1C, the initial specific capacity is as high as 683.02mAh g -1 , and the capacity is still 586.3mAh g -1 after 100 cycles; at 4C, the initial specific capacity is as high as 541.21mAh g -1 , and the capacity is still 388.56mAh g -1 after 500 cycles; the high-rate performance has good capacity and cycle stability. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a scanning electron microscope image of the hollow network spherical structure Co-CoSe@C heterostructure prepared in Example 1 of the present application;

[0034] Figure 2 is a transmission electron microscope image of the lithium-sulfur battery composite material of the hollow network spherical structure Co-CoSe@C heterostructure prepared in Example 1 of the present application;

[0035] Figure 3 is an EDS image of the lithium-sulfur battery composite material of the hollow network spherical structure Co-CoSe@C heterostructure prepared in Example 1 of the present application;

[0036] Figure 4 is an X-ray diffraction pattern of the hollow network spherical structure Co-CoSe@C heterostructure prepared in Example 1 of the present application, the Co@C composite material prepared in Comparative Example 1 and the CoSe@C composite material prepared in Comparative Example 2;

[0037] Figure 5 is a 0.1-5C rate performance graph of the hollow network spherical structure Co-CoSe@C heterostructure prepared in Example 1 of the present application, the Co@C composite material prepared in Comparative Example 1 and the CoSe@C composite material prepared in Comparative Example 2;

[0038] Figure 6 is a cycle performance graph at 1C rate of the hollow network spherical structure Co-CoSe@C heterostructure prepared in Example 1 of the present application, the Co@C composite material prepared in Comparative Example 1 and the CoSe@C composite material prepared in Comparative Example 2;

[0039] Figure 7is a cycle performance graph of the Co-CoSe@C heterostructure lithium-sulfur battery composite material of the hollow reticular spherical structure prepared in Example 1 of the present application at a 4C rate. DETAILED DESCRIPTION

[0040] The present application will be further described below in conjunction with the drawings and specific examples, so that those of ordinary skill in the art can better understand the implementation of the present application, but the scope of protection of the present application is not limited thereto.

[0041] The methods described in the embodiments of the present application are all conventional methods unless otherwise specified. The materials, reagents, etc. used are all commercially available unless otherwise specified.

[0042] In the following description of the present embodiment, the order of the serial numbers does not mean the order of execution, and some or all steps can be executed in parallel or in sequence, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the present embodiment.

[0043] In the following description of the present embodiment, the numerical range should be understood as also specifically disclosing each intermediate value between the upper limit and the lower limit of the range. Each smaller range between any stated value or intermediate value in a stated range and any other stated value or intermediate value in the stated range is also included in the present embodiment, and the upper limit and the lower limit of the smaller range can be independently included or excluded from the range.

[0044] Unless otherwise specified, the technical / scientific terms used in the present embodiment have the same meaning as generally understood by those of ordinary skill in the art to which the present application belongs. Although only preferred methods and materials are described in the present application, any methods and materials similar or equivalent to those described in the present application can also be used in the implementation or testing of the present application.

[0045] Example 1

[0046] Step 1, take 150 mL of deionized water, 700 mL of anhydrous ethanol, 50 mL of ammonia water into a beaker and stir; then add 30 mL of tetraethyl orthosilicate and stir; then add 5 g of resorcinol and 5.6 mL of formaldehyde in sequence, and stir for 24 h; finally, centrifuge, dry at 70°C, and grind to obtain phenolic resin precursor powder.

[0047] Step 2, take the precursor powder obtained in Step 1, heat to 800°C under an argon atmosphere, keep for 5 h, cool to room temperature with the furnace, and obtain carbon spheres templated with silica.

[0048] Step 3, disperse the carbon spheres obtained in Step 2 in 300 mL of 30% hydrofluoric acid solution and stir for 48 h to remove silica, then wash multiple times until the solution is neutral, and then vacuum dry to obtain hollow carbon spheres.

[0049] Step 4, 200 mg of the hollow carbon spheres obtained in Step 3 were dispersed in a mixed aqueous solution of 120 mL of 1 mmol of cobalt nitrate hexahydrate and 2 mmol of dicyandiamide; then, a precursor sample was obtained by drying in an oil bath at 120°C; finally, the precursor sample was heated to 800°C under an argon atmosphere, and the temperature was maintained for 4 h, and the furnace was cooled to room temperature, to obtain a cobalt-containing precursor powder of the hollow network spherical structure of "carbon sphere-carbon nanotube".

[0050] Step 5, the cobalt-containing precursor powder obtained in Step 4 and selenium powder were placed at both ends of a crucible in a mass ratio of 1:0.7, and the selenium powder was placed upstream of the atmosphere; then, the mixture was heated to 600°C under a mixed atmosphere of argon and hydrogen, and the temperature was maintained for 2 h, and the furnace was cooled to room temperature, to obtain a Co-CoSe@C heterostructure material of the hollow network spherical structure of "carbon sphere-carbon nanotube".

[0051] Step 6, 100 mg of the Co-CoSe@C heterostructure material of the hollow network spherical structure obtained in Step 5 and 400 mg of elemental sulfur were dispersed in 20 mL of a mixed solution of carbon disulfide and 10 mL of N-methylpyrrolidone, and the solvent was evaporated in an oil bath at 70°C; finally, a sulfur-loaded Co-CoSe@C heterostructure composite material of the hollow network spherical structure of "carbon sphere-carbon nanotube" was obtained after being maintained at 200°C under an argon atmosphere for 30 min.

[0052] Example 2

[0053] Step 1, 150 mL of deionized water, 700 mL of anhydrous ethanol, and 50 mL of ammonia water were added to a beaker and stirred; then, 30 mL of tetraethyl orthosilicate was added and stirred; then, 3 g of resorcinol and 4.6 mL of formaldehyde were added in sequence, and stirred for 24 h; finally, the phenolic resin precursor powder was obtained by centrifugation, drying at 70°C, and grinding.

[0054] Step 2, the precursor powder obtained in Step 1 was heated to 800°C under an argon atmosphere, and the temperature was maintained for 5 h, and the furnace was cooled to room temperature, to obtain carbon spheres templated by silica.

[0055] Step 3, the carbon spheres obtained in Step 2 were dispersed in 300 mL of a 30% hydrogen fluoride acid solution and stirred for 48 h to remove the silica, and then washed multiple times until the solution was neutral; then, the hollow carbon spheres were obtained by vacuum drying.

[0056] Step 4, 200 mg of hollow carbon spheres obtained in step 3 were dispersed in 120 mL of a mixed solution of 1 mmol of cobalt nitrate hexahydrate and 2 mmol of dicyandiamide; then, a precursor sample was obtained by drying in an oil bath at 120°C; finally, heated to 800°C under an argon atmosphere, and kept for 4 h, and then cooled to room temperature in the furnace, to obtain a cobalt-containing precursor powder of "carbon sphere-carbon nanotube" hollow reticular spherical structure.

[0057] Step 5, the cobalt-containing precursor powder obtained in step 4 was placed in a crucible with selenium powder at a mass ratio of 1:0.7, and the selenium powder was placed upstream of the atmosphere; then heated to 600°C under a mixed atmosphere of argon and hydrogen, and kept for 2 h, and then cooled to room temperature in the furnace, to obtain a Co-CoSe@C heterostructure material of "carbon sphere-carbon nanotube" hollow reticular spherical structure.

[0058] Step 6, 100 mg of the Co-CoSe@C heterostructure material of hollow reticular spherical structure obtained in step 5 was dispersed with 400 mg of elemental sulfur in 20 mL of a mixed solution of carbon disulfide and 10 mL of N-methylpyrrolidone, and then solvent was evaporated in an oil bath at 70°C, and finally a sulfur-loaded Co-CoSe@C heterostructure composite material of "carbon sphere-carbon nanotube" hollow reticular spherical structure was obtained after keeping at 200°C for 30 min under an argon atmosphere.

[0059] Example 3

[0060] Step 1, 150 mL of deionized water, 700 mL of anhydrous ethanol, and 50 mL of ammonia water were added to a beaker and stirred; then 30 mL of tetraethyl orthosilicate was added and stirred; then 7 g of resorcinol and 6.6 mL of formaldehyde were added in sequence, and stirred for 24 h; finally, the phenolic resin precursor powder was obtained by centrifugation, drying at 70°C, and grinding.

[0061] Step 2, the precursor powder obtained in step 1 was heated to 800°C under an argon atmosphere, and kept for 5 h, and then cooled to room temperature in the furnace, to obtain carbon spheres templated by silica.

[0062] Step 3, the carbon spheres obtained in step 2 were dispersed in 300 mL of a 30% concentrated hydrofluoric acid solution and stirred for 48 h to remove the silica, and then washed multiple times until the solution was neutral, and then vacuum dried to obtain hollow carbon spheres.

[0063] Step 4, 200 mg of hollow carbon spheres obtained in step 3 were dispersed in 120 mL of a mixed solution of 1 mmol of cobalt nitrate hexahydrate and 2 mmol of dicyandiamide; then, a precursor sample was obtained by drying in an oil bath at 120°C; finally, heated to 800°C under an argon atmosphere, and kept for 4 h, and then cooled to room temperature in the furnace, to obtain a cobalt-containing precursor powder of "carbon sphere-carbon nanotube" hollow reticular spherical structure.

[0064] Step 5, the cobalt precursor powder obtained in step 4 and selenium powder were placed at both ends of the crucible in a mass ratio of 1:0.7, and the selenium powder was placed upstream of the atmosphere; then heated to 600°C under a mixed atmosphere of argon and hydrogen, and kept for 2h, and cooled to room temperature in the furnace, to obtain a "carbon sphere-carbon nanotube" hollow network spherical structure Co-CoSe@C heterostructure material.

[0065] Step 6, 100mg of the hollow network spherical structure Co-CoSe@C heterostructure material obtained in step 5 was dispersed with 400mg of elemental sulfur in 20mL of a mixed solution of carbon disulfide and 10mL of N-methyl pyrrolidone, and then evaporated to dryness by solvent in an oil bath at 70°C, and finally a sulfur-loaded "carbon sphere-carbon nanotube" hollow network spherical structure Co-CoSe@C heterostructure composite material was obtained after heat treatment at 200°C for 30min in an argon atmosphere.

[0066] Example 4

[0067] Step 1, 150mL of deionized water, 700mL of anhydrous ethanol, and 50mL of ammonia water were added to a beaker and stirred; then 30mL of tetraethyl orthosilicate was added and stirred; then 5g of resorcinol and 5.6mL of formaldehyde were added in sequence, and stirred for 24h; finally, the phenolic aldehyde resin precursor powder was obtained by centrifugation, drying at 70°C, and grinding.

[0068] Step 2, the precursor powder obtained in step 1 was heated to 750°C under an argon atmosphere, and kept for 5h, and then cooled to room temperature in the furnace, to obtain carbon spheres templated with silica.

[0069] Step 3, the carbon spheres obtained in step 2 were dispersed in 300mL of a 30% hydrogen fluoride acid solution and stirred for 48h to remove the silica, and then washed multiple times until the solution was neutral, and then vacuum dried to obtain hollow carbon spheres.

[0070] Step 4, 200mg of the hollow carbon spheres obtained in step 3 were dispersed in 120mL of a mixed solution of 1mmol of cobalt nitrate hexahydrate and 2mmol of dicyandiamide; then, the precursor sample was obtained by drying in an oil bath at 120°C; finally, heated to 800°C under an argon atmosphere, and kept for 4h, and then cooled to room temperature in the furnace, to obtain a "carbon sphere-carbon nanotube" hollow network spherical structure cobalt-containing precursor powder.

[0071] Step 5, the cobalt precursor powder obtained in step 4 and selenium powder were placed at both ends of the crucible in a mass ratio of 1:0.7, and the selenium powder was placed upstream of the atmosphere; then heated to 600°C under a mixed atmosphere of argon and hydrogen, and kept for 2h, and cooled to room temperature in the furnace, to obtain a "carbon sphere-carbon nanotube" hollow network spherical structure Co-CoSe@C heterostructure material.

[0072] Step 6, 100 mg of the hollow reticular spherical structure of Co-CoSe@C heterostructure material obtained in step 5 was dispersed in 20 mL of a mixed solution of carbon disulfide and 10 mL of N-methylpyrrolidone with 400 mg of elemental sulfur, and then solvent was evaporated in an oil bath at 70°C. Finally, after being kept at 200°C for 30 min in an argon atmosphere, the sulfur-loaded "carbon sphere-carbon nanotube" hollow reticular spherical structure of Co-CoSe@C heterostructure composite material was obtained.

[0073] Example 5

[0074] Step 1, 150 mL of deionized water, 700 mL of anhydrous ethanol, and 50 mL of ammonia water were added to a beaker and stirred. Then, 30 mL of tetraethyl orthosilicate was added and stirred. Then, 5 g of resorcinol and 5.6 mL of formaldehyde were added in sequence and stirred for 24 h. Finally, after centrifugation, drying at 70°C, and grinding, a phenolic resin precursor powder was obtained.

[0075] Step 2, the precursor powder obtained in step 1 was heated to 850°C under an argon atmosphere and kept for 5 h. The furnace was cooled to room temperature to obtain carbon spheres templated by silica.

[0076] Step 3, the carbon spheres obtained in step 2 were dispersed in 300 mL of a 30% hydrofluoric acid solution and stirred for 48 h to remove the silica. Then, the solution was washed to neutral, and then vacuum dried to obtain hollow carbon spheres.

[0077] Step 4, 200 mg of the hollow carbon spheres obtained in step 3 were dispersed in 120 mL of a mixed solution of 1 mmol of cobalt nitrate hexahydrate and 2 mmol of dicyandiamide. Then, a precursor sample was obtained by drying in an oil bath at 120°C. Finally, it was heated to 800°C under an argon atmosphere and kept for 4 h. The furnace was cooled to room temperature to obtain a "carbon sphere-carbon nanotube" hollow reticular spherical structure of cobalt-containing precursor powder.

[0078] Step 5, the cobalt-containing precursor powder obtained in step 4 was placed at both ends of the crucible with selenium powder placed upstream of the atmosphere in a mass ratio of 1:0.7. Then, it was heated to 600°C under a mixed atmosphere of argon and hydrogen and kept for 2 h. The furnace was cooled to room temperature to obtain a "carbon sphere-carbon nanotube" hollow reticular spherical structure of Co-CoSe@C heterostructure material.

[0079] Step 6, 100 mg of the hollow reticular spherical structure of Co-CoSe@C heterostructure material obtained in step 5 was dispersed in 20 mL of a mixed solution of carbon disulfide and 10 mL of N-methylpyrrolidone with 400 mg of elemental sulfur, and then solvent was evaporated in an oil bath at 70°C. Finally, after being kept at 200°C for 30 min in an argon atmosphere, the sulfur-loaded "carbon sphere-carbon nanotube" hollow reticular spherical structure of Co-CoSe@C heterostructure composite material was obtained.

[0080] Example 6

[0081] Step 1, 150 mL of deionized water, 700 mL of anhydrous ethanol, and 50 mL of ammonia water were added to a beaker and stirred. Then, 30 mL of tetraethyl orthosilicate was added and stirred. Then, 5 g of resorcinol and 5.6 mL of formaldehyde were added in sequence and stirred for 24 h. Finally, after centrifugation, drying at 70°C, and grinding, a phenolic resin precursor powder was obtained.

[0082] Step 2, the precursor powder obtained in step 1 was heated to 800°C under an argon atmosphere and kept for 5 h. The furnace was cooled to room temperature to obtain carbon spheres templated by silicon dioxide.

[0083] Step 3, the carbon spheres obtained in step 2 were dispersed in 300 mL of a 30% hydrofluoric acid solution and stirred for 48 h to remove the silicon dioxide. Then, the solution was washed to neutral, and then vacuum dried to obtain hollow carbon spheres.

[0084] Step 4, 200 mg of the hollow carbon spheres obtained in step 3 were dispersed in 120 mL of a mixed solution of 1 mmol of cobalt nitrate hexahydrate and 2 mmol of dicyandiamide. Then, a precursor sample was obtained by drying in an oil bath at 120°C. Finally, it was heated to 750°C under an argon atmosphere and kept for 4 h. The furnace was cooled to room temperature to obtain a "carbon sphere-carbon nanotube" hollow reticular spherical structure of cobalt-containing precursor powder.

[0085] Step 5, the cobalt-containing precursor powder obtained in step 4 was placed at both ends of the crucible with selenium powder placed upstream in the atmosphere. Then, it was heated to 600°C under a mixed atmosphere of argon and hydrogen and kept for 2 h. The furnace was cooled to room temperature to obtain a "carbon sphere-carbon nanotube" hollow reticular spherical structure of Co-CoSe@C heterostructure material.

[0086] Step 6, 100 mg of the hollow reticular spherical structure of Co-CoSe@C heterostructure material obtained in step 5 was dispersed in 20 mL of a mixed solution of carbon disulfide and 10 mL of N-methylpyrrolidone with 400 mg of elemental sulfur, and was evaporated by solvent at 70°C in an oil bath, and finally obtained the sulfur-loaded "carbon sphere-carbon nanotube" hollow reticular spherical structure of Co-CoSe@C heterostructure composite material after heat preservation at 200°C for 30 min in an argon atmosphere.

[0087] Example 7

[0088] Step 1, 150 mL of deionized water, 700 mL of anhydrous ethanol, 50 mL of ammonia water were added to a beaker and stirred; then 30 mL of tetraethyl orthosilicate was added and stirred; then 5 g of resorcinol and 5.6 mL of formaldehyde were added in turn, and stirred for 24 h; finally, the phenolic resin precursor powder was obtained by centrifugation, drying at 70°C, and grinding.

[0089] Step 2, the precursor powder obtained in step 1 was heated to 800°C under an argon atmosphere and heat preserved for 5 h, and the furnace was cooled to room temperature to obtain carbon spheres templated by silicon dioxide.

[0090] Step 3, the carbon spheres obtained in step 2 were dispersed in 300 mL of a 30% hydrogen fluoride acid solution and stirred for 48 h to remove the silicon dioxide, and then washed multiple times until the solution was neutral, and then vacuum dried to obtain hollow carbon spheres.

[0091] Step 4, 200 mg of the hollow carbon spheres obtained in step 3 were dispersed in 120 mL of a mixed solution of 1 mmol of cobalt nitrate hexahydrate and 2 mmol of dicyandiamide; then, the precursor sample was obtained by drying in an oil bath at 120°C; finally, it was heated to 850°C under an argon atmosphere and heat preserved for 4 h, and the furnace was cooled to room temperature to obtain a "carbon sphere-carbon nanotube" hollow reticular spherical structure of cobalt-containing precursor powder.

[0092] Step 5, the cobalt-containing precursor powder obtained in step 4 was placed at both ends of the crucible with selenium powder placed upstream of the atmosphere in a mass ratio of 1:0.7; then it was heated to 600°C under a mixed atmosphere of argon and hydrogen and heat preserved for 2 h, and the furnace was cooled to room temperature to obtain a "carbon sphere-carbon nanotube" hollow reticular spherical structure of Co-CoSe@C heterostructure material.

[0093] Step 6, 100 mg of the hollow reticular spherical structure of Co-CoSe@C heterostructure material obtained in step 5 was dispersed in 20 mL of a mixed solution of carbon disulfide and 10 mL of N-methylpyrrolidone with 400 mg of elemental sulfur, and then solvent was evaporated in an oil bath at 70°C. Finally, after being kept at 200°C for 30 min in an argon atmosphere, the sulfur-loaded "carbon sphere-carbon nanotube" hollow reticular spherical structure of Co-CoSe@C heterostructure composite material was obtained.

[0094] Example 8

[0095] Step 1, 150 mL of deionized water, 700 mL of anhydrous ethanol, and 50 mL of ammonia water were added to a beaker and stirred. Then, 30 mL of tetraethyl orthosilicate was added and stirred. Then, 5 g of resorcinol and 5.6 mL of formaldehyde were added in sequence and stirred for 24 h. Finally, after centrifugation, drying at 70°C, and grinding, a phenolic resin precursor powder was obtained.

[0096] Step 2, the precursor powder obtained in step 1 was heated to 800°C under an argon atmosphere and kept for 5 h. The furnace was cooled to room temperature to obtain carbon spheres templated by silica.

[0097] Step 3, the carbon spheres obtained in step 2 were dispersed in 300 mL of a 30% hydrofluoric acid solution and stirred for 48 h to remove the silica. Then, the solution was washed to neutral, and then vacuum dried to obtain hollow carbon spheres.

[0098] Step 4, 200 mg of the hollow carbon spheres obtained in step 3 were dispersed in 120 mL of a mixed solution of 1 mmol of cobalt nitrate hexahydrate and 2 mmol of dicyandiamide. Then, a precursor sample was obtained by drying in an oil bath at 120°C. Finally, it was heated to 800°C under an argon atmosphere and kept for 4 h. The furnace was cooled to room temperature to obtain a "carbon sphere-carbon nanotube" hollow reticular spherical structure of cobalt-containing precursor powder.

[0099] Step 5, the cobalt-containing precursor powder obtained in step 4 was placed at both ends of the crucible with selenium powder placed upstream in the atmosphere. Then, it was heated to 550°C under a mixed atmosphere of argon and hydrogen and kept for 2 h. The furnace was cooled to room temperature to obtain a "carbon sphere-carbon nanotube" hollow reticular spherical structure of Co-CoSe@C heterostructure material.

[0100] Step 6, 100 mg of the hollow reticular spherical structure of Co-CoSe@C heterostructure material obtained in step 5 was dispersed in 20 mL of a mixed solution of carbon disulfide and 10 mL of N-methylpyrrolidone with 400 mg of elemental sulfur, and then solvent was evaporated in an oil bath at 70°C. Finally, after being kept at 200°C for 30 min in an argon atmosphere, the sulfur-loaded "carbon sphere-carbon nanotube" hollow reticular spherical structure of Co-CoSe@C heterostructure composite material was obtained.

[0101] Example 9

[0102] Step 1, 150 mL of deionized water, 700 mL of anhydrous ethanol, and 50 mL of ammonia water were added to a beaker and stirred. Then, 30 mL of tetraethyl orthosilicate was added and stirred. Then, 5 g of resorcinol and 5.6 mL of formaldehyde were added in sequence and stirred for 24 h. Finally, after centrifugation, drying at 70°C, and grinding, a phenolic resin precursor powder was obtained.

[0103] Step 2, the precursor powder obtained in step 1 was heated to 800°C under an argon atmosphere and kept for 5 h. The furnace was cooled to room temperature to obtain carbon spheres templated by silicon dioxide.

[0104] Step 3, the carbon spheres obtained in step 2 were dispersed in 300 mL of a 30% hydrogen fluoride acid solution and stirred for 48 h to remove the silicon dioxide. Then, the solution was washed to neutral several times, and then vacuum dried to obtain hollow carbon spheres.

[0105] Step 4, 200 mg of the hollow carbon spheres obtained in step 3 were dispersed in 120 mL of a mixed solution of 1 mmol of cobalt nitrate hexahydrate and 2 mmol of dicyandiamide. Then, a precursor sample was obtained by drying in an oil bath at 120°C. Finally, it was heated to 800°C under an argon atmosphere and kept for 4 h. The furnace was cooled to room temperature to obtain a "carbon sphere-carbon nanotube" hollow reticular spherical structure of cobalt-containing precursor powder.

[0106] Step 5, the cobalt-containing precursor powder obtained in step 4 was placed at both ends of the crucible with selenium powder placed upstream of the atmosphere in a mass ratio of 1:0.7. Then, it was heated to 650°C under a mixed atmosphere of argon and hydrogen and kept for 2 h. The furnace was cooled to room temperature to obtain a "carbon sphere-carbon nanotube" hollow reticular spherical structure of Co-CoSe@C heterostructure material.

[0107] Step 6, 100 mg of hollow reticulated spherical structure of Co-CoSe@C heterostructure material obtained from step 5 was dispersed into 20 mL of carbon disulfide and 10 mL of N-methyl pyrrolidone mixed solution with 400 mg of elemental sulfur, and then the solvent was evaporated by oil bath at 70°C. Finally, the sulfur-loaded "carbon sphere-carbon nanotube" hollow reticulated spherical structure of Co-CoSe@C heterostructure composite material was obtained after heat preservation at 200°C for 30 min in an argon atmosphere.

[0108] Comparative Example 1: Preparation method of Co@C

[0109] The hollow reticulated spherical structure of Co@C lithium-sulfur battery composite material and its preparation method provided by Comparative Example 1 are different from the preparation method of the Co-CoSe@C heterostructure material of Example 1 only in that the vapor deposition selenization process in step 5 is cancelled, and the other steps are completely consistent with the Co-CoSe@C heterostructure material method.

[0110] Comparative Example 2: Preparation method of CoSe@C

[0111] The hollow reticulated spherical structure of CoSe@C lithium-sulfur battery composite material and its preparation method provided by Comparative Example 2 are different from the preparation method of the Co-CoSe@C heterostructure material of Example 1 only in that the mass ratio of cobalt precursor powder to selenium powder in the vapor deposition selenization process in step 5 is adjusted from 1:0.7 to 1:1, and the other steps are completely consistent with the Co-CoSe@C heterostructure material method.

[0112] Preparation of the battery:

[0113] The positive electrode material prepared in Examples 1-9 and Comparative Examples 1-2 above was used as the active material, Ketjen black was used as the conductive agent, PVDF was used as the binder, and N-methyl-2-pyrrolidone (NMP) was used as the dispersing agent. The mass ratio of the positive electrode material: Ketjen black: PVDF was 7:2:1. In a total of 200 mg of the above three materials, 30-35 drops of NMP were added dropwise to make a slurry, which was coated on a carbon-containing aluminum foil and placed in a vacuum oven at 60°C for 12 h. Then, the sample was cut into a 12 mm round piece as a positive electrode sheet. Then, a metal lithium sheet was used as the negative electrode, a polypropylene microporous membrane was used as the separator, and 1 M LiTFSI in DME:DOL=1:1 Vol% with 1% LiNO3 was used as the electrolyte. A CR2032 type button cell was prepared in an argon-filled glove box.

[0114] Testing and performance:

[0115] The coin cells prepared from the positive electrode materials of Example 1 and Comparative Example 1-2 were tested for rate performance in the voltage range of 1.7-2.8 V and at current densities of 0.1 C, 0.5 C, 1 C, 2 C, 4 C, 5 C and 0.2 C, and the results are shown in Table 1. Figure 5

[0116] The coin cells prepared from the positive electrode materials of Example 1 and Comparative Example 1-2 were tested for cycle stability in the voltage range of 1.7-2.8 V, and after two cycles of activation at a current density of 0.1 C, 100 cycles were tested at a current density of 1 C, and the results are shown in Table 2. Figure 6

[0117] The coin cells prepared from the positive electrode material of Example 1 were tested for cycle stability in the voltage range of 1.7-2.8 V, and after two cycles of activation at a current density of 0.1 C, 500 cycles were tested at a current density of 4 C, and the results are shown in Table 3. Figure 7

[0118] Figure 1 The scanning electron microscope image of the Co-CoSe@C heterostructure of the hollow reticular spherical structure prepared in Example 1 of the present application. The sample presents a hollow spherical shape, and the carbon spheres after loading of sulfur still maintain a high degree of sphericity, the carbon nanotubes are distributed in the spheres in a reticular structure, and the heterostructure particles are dispersed in the carbon nanotubes, and the diameter of the spheres is about 250 nm.

[0119] Figure 2 The transmission electron microscope image of the Co-CoSe@C heterostructure of the hollow reticular spherical structure prepared in Example 1 of the present application. The morphology observed by the transmission electron microscope is consistent with that observed by the scanning electron microscope Figure 1 , further confirming the unique features of the morphology of the material.

[0120] Figure 3 The EDS image of the Co-CoSe@C heterostructure of the hollow reticular spherical structure prepared in Example 1 of the present application. The EDS element distribution map further confirms the uniform distribution of Co and Se elements in the material.

[0121] Figure 4 The XRD image of the Co-CoSe@C heterostructure of the hollow reticular spherical structure prepared in Example 1 of the present application, and the Co@C heterostructure prepared in Comparative Example 1 and the CoSe@C heterostructure prepared in Comparative Example 2. Compared with the XRD images of the Co@C heterostructure and CoSe@C, all the diffraction peaks of the Co-CoSe@C heterostructure of the hollow reticular spherical structure of Example 1 can be well matched with the PDF standard card: PDF#15-0806 and PDF#97-062-4983, the characteristic peaks of the heterostructure are complete and there is no impurity phase, indicating that it is successfully constructed.​​​

[0122] Figure 5 The rate performance plots of the hollow reticular spherical structure Co-CoSe@C heterostructure lithium-sulfur battery composite material prepared in Example 1 of the present application and Comparative Examples 1-2 were tested in the voltage range of 1.8-4.0 V. At current densities of 0.1, 0.2, 0.5, 1.0, 2.0, 4.0 and 5.0 C, the specific capacity of the hollow reticular spherical structure Co-CoSe@C heterostructure lithium-sulfur battery composite material of Example 1 was higher at 0.1, 0.2, 0.5, 1.0, 2.0, 4.0 C and 5.0 C, respectively, and exhibited excellent rate performance. This is because the Co and CoSe nanoparticles in the Co-CoSe@C heterostructure are uniformly dispersed in the carbon matrix, forming abundant active sites. These active sites can effectively adsorb polysulfides, on the one hand reducing the dissolution and shuttling of polysulfides in the electrolyte, and on the other hand promoting the rapid conversion of polysulfides, thereby accelerating the charge transfer process.

[0123] Figure 6 The cycle performance plots of the hollow reticular spherical structure Co-CoSe@C heterostructure lithium-sulfur battery composite material prepared in Example 1 of the present application and Comparative Examples 1-2 were tested at a current density of 1 C. The initial specific capacity of Example 1 was 683.02 mAh / g, and after 100 cycles, the discharge specific capacity was 586.3 mAh / g, with a capacity retention rate of 85.8%. The initial discharge specific capacity of Comparative Example 1 was 602.8 mAh / g, and after 100 cycles, the discharge specific capacity was 449.7 mAh / g, with a capacity retention rate of 74.6%. The initial specific capacity of Comparative Example 2 was 519.63 mAh / g, and after 100 cycles, the discharge specific capacity was 436.2 mAh / g, with a capacity retention rate of 83.9%. It can be seen that, compared with Co@C and CoSe@C, the hollow reticular spherical structure Co-CoSe@C heterostructure of the present application has higher specific capacity and capacity retention rate. This is because the hollow reticular spherical structure Co-CoSe@C heterostructure can accelerate the adsorption and conversion of polysulfides, and during the charging and discharging process, polysulfides can be effectively confined inside the hollow structure, reducing their shuttling in the electrolyte, thereby inhibiting the loss of active material. In addition, the Co-CoSe@C heterostructure itself has good electrical conductivity, which cooperates with the carbon matrix to accelerate the charge transfer.

[0124] Figure 7The cycle performance graph of the hollow reticular spherical structure Co-CoSe@C heterostructure lithium-sulfur battery composite material prepared for the embodiment 1 of the present application is tested at a current density of 4C. The initial specific capacity of embodiment 1 is 541.2 mAh / g, and the discharge specific capacity is 338.6 mAh / g after 500 cycles, and the capacity retention rate is 62.6%. It can be seen that the hollow reticular spherical structure Co-CoSe@C heterostructure lithium-sulfur battery composite material still has good cycle performance after 500 cycles at high rate. Because the unique hollow reticular spherical design of the Co-CoSe@C heterostructure can provide sufficient storage space for polysulfides, effectively inhibits the shuttle effect of polysulfides, thereby reducing the loss of active materials. At the same time, the reticular spherical structure increases the specific surface area of the material, so that the contact between the electrode and the electrolyte is more sufficient, promoting the rapid diffusion of ions and the efficient transmission of electric charge.

[0125] In summary, the present application uses the Co-CoSe@C heterostructure composite material with a "carbon sphere-carbon nanotube" hollow reticular spherical structure as a lithium-sulfur battery positive electrode material, and compared with materials without the heterostructure, the rate and cycle performance are better, and the discharge specific capacity is higher, which benefits from the unique structure design. The "carbon sphere-carbon nanotube" hollow reticular spherical Co-CoSe@C heterostructure due to the unique staggered network structure, helps to fix the additional active material to the carbon nanotubes inside the shell layer, thereby increasing the contact area between the catalytic host and the active material, reducing the size of the active material inside the sphere, significantly improving the chemical adsorption capacity and catalytic activity of polysulfides, effectively relieving the shuttle effect and improving the reaction kinetics of lithium-sulfur batteries.

[0126] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having the same technical idea and playing the same role and effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications of the embodiments that can be thought of by those skilled in the art, and other ways constructed by combining part of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A Co-CoSe@C heterostructure composite of sulfur-loaded hollow reticulated spherical structure for lithium-sulfur batteries, characterized in that: The composite material comprises a hollow reticular spherical structure of "carbon sphere-carbon nanotube", the carbon nanotube is on the surface or inside of the carbon sphere, the Co-CoSe is uniformly distributed in the hollow carbon sphere material and the carbon nanotube inside the sphere, and the sulfur is loaded on the Co-CoSe@C heterostructure composite material of the hollow reticular spherical structure.

2. The Co-CoSe@C heterostructure composite of hollow network-spherical sulfur- loaded structure for lithium-sulfur batteries according to claim 1, characterized in that, The content of carbon in the composite material is 85% to 98%, the content of Co is 1% to 10%, the content of Se is 1% to 10%, and the content of sulfur is 65% to 80%; Preferably, the content of carbon in the composite material is 90% to 95%, the content of Co is 1% to 5%, the content of Se is 1% to 3%, and the content of sulfur is 68% to 75%; The inner diameter of the hollow carbon sphere cavity is 200 to 300 nm, and the carbon layer thickness is 15 to 35 nm.

3. A method for the preparation of Co-CoSe@C heterostructure composite of sulfur- loaded hollow networked spherical structures for lithium-sulfur batteries according to any one of claims 1-2, characterized in that, The method comprises the following steps: Step 1, preparing a phenolic resin precursor powder; Step 2, obtaining a carbon sphere with a silica template after high-temperature carbonization of the precursor powder obtained in step 1; Step 3, obtaining a hollow carbon sphere after acid washing etching and drying of the carbon sphere obtained in step 2; Step 4, dispersing the hollow carbon sphere obtained in step 3 in a solution containing cobalt, stirring, oil bath evaporation, and high-temperature pyrolysis to obtain a precursor powder containing cobalt comprising a hollow reticular spherical structure of "carbon sphere-carbon nanotube"; Step 5, obtaining a Co-CoSe@C heterostructure material comprising a hollow reticular spherical structure of "carbon sphere-carbon nanotube" after gas phase deposition of selenium of the precursor powder containing cobalt comprising a hollow reticular spherical structure of "carbon sphere-carbon nanotube" obtained in step 4; Step 6, obtaining a sulfur-loaded Co-CoSe@C heterostructure lithium-sulfur battery composite material comprising a hollow reticular spherical structure of "carbon sphere-carbon nanotube" by a liquid phase method of the Co-CoSe@C heterostructure material comprising a hollow reticular spherical structure of "carbon sphere-carbon nanotube" obtained in step 5 and elemental sulfur.

4. The production method according to claim 3, characterized by, The step 1 specifically comprises weighing raw materials, stirring, drying, and grinding to obtain a phenolic resin precursor powder; The raw materials specifically comprise 100-200 mL of deionized water, 600-800 mL of anhydrous ethanol, 30-70 mL of ammonia water, 20-40 mL of tetraethyl orthosilicate, 3-8 g of resorcinol, and 4-7 mL of formaldehyde; The stirring time in the step 1 is 20-30 h, and the drying temperature is 65-75 ℃.

5. The preparation method according to claim 3, characterized in that, The high-temperature carbonization process in the step 2 is to heat the precursor powder obtained in step 1 to 700-900 ℃, and keep the temperature for 5 h to obtain a carbon sphere with a silica template; The acid washing etching process in the step 3 is to place the carbon sphere obtained in step 2 in a 30% hydrofluoric acid solution, keep for 40-56 h, wash until the solution is neutral, and vacuum dry.

6. The preparation method according to claim 3, characterized in that, The step 4 is to weigh 150-250 mg of the hollow carbon sphere obtained in step 3, disperse it in 100-150 mL of a solution containing cobalt, stir, oil bath evaporate, and high-temperature pyrolyze to obtain a precursor powder containing cobalt comprising a hollow reticular spherical structure of "carbon sphere-carbon nanotube"; The solution containing cobalt specifically includes cobalt nitrate hexahydrate, dicyandiamide, and deionized water as a solvent; the cobalt nitrate hexahydrate is 0.5-2 mmol, and the dicyandiamide is 1-4 mmol. In step 4, the oil bath evaporation temperature is 110-140℃; the high-temperature pyrolysis specifically refers to heating the sample after oil bath evaporation to 700-900℃, and keeping the temperature for 3-5h.

7. The preparation method according to claim 3, characterized in that, In step 5, the process of vapor deposition selenization is as follows: the precursor powder obtained in step 4 is heated to 500-700℃ together with selenium powder, and kept for 1.5-3h to obtain the Co-CoSe@C heterostructure material with "carbon sphere-carbon nanotube" hollow reticular spherical structure; the mass ratio of the precursor powder to the selenium powder is 1:0.5-0.

8.

8. The preparation method according to claim 3, characterized in that, In step 6, 80-150mg of the Co-CoSe@C heterostructure material with "carbon sphere-carbon nanotube" hollow reticular spherical structure obtained in step 5 is dispersed in 350-500mg of elemental sulfur in 15-30mL of a mixed solution of carbon bisulfide and 5-15mL of N-methylpyrrolidone, and then solvent is evaporated in an oil bath at 70℃, and finally the Co-CoSe@C heterostructure composite material with sulfur after loading is obtained by keeping the temperature at 200℃ in an argon atmosphere for 30min.

9. A method for preparing a lithium-sulfur battery cathode material, characterized in that, The sulfur-loaded Co-CoSe@C heterostructure composite material with hollow reticular spherical structure of any one of claims 1-2 or the sulfur-loaded Co-CoSe@C heterostructure composite material with hollow reticular spherical structure obtained by the preparation method of any one of claims 3-8 is mixed with conductive carbon black and polyvinylidene fluoride according to a mass ratio of 7:2:1, and an electrode coating method is used to obtain a sulfur-loaded Co-CoSe@C / S heterostructure lithium-sulfur battery anode material with hollow reticular spherical structure.

10. A lithium-sulfur battery, characterized by, The lithium-sulfur battery anode material of claim 9 is included.

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