Lithium-sulfur battery positive electrode material, preparation method thereof and all-solid-state lithium-sulfur battery

Abstract

The invention belongs to the technical field of lithium-sulfur batteries, and discloses a lithium-sulfur battery positive electrode material, a preparation method thereof and an all-solid-state lithium-sulfur battery. The lithium-sulfur battery positive electrode material provided by the invention is a sulfur-high halogen sulfide-carbon nanotube-graphene composite material, and has good ionic conductivity and electronic conductivity. The all-solid-state lithium-sulfur battery provided by the invention consists of a sulfur positive electrode, a solid-state electrolyte membrane, a conductive membrane and a lithium negative electrode, a sulfur positive electrode contains the sulfur-high halogen sulfide-carbon nanotube-graphene composite material and a binder, and a conductive film is used as a protective layer between a solid electrolyte and a lithium negative electrode, so that side reaction caused by direct contact and short circuit caused by lithium dendrites are avoided. The all-solid-state lithium-sulfur battery is excellent in rate and quick charge performance, good in cycle performance and high in safety, the preparation method is feasible in process, and large-scale production can be achieved.

Description

Technical Field

[0001] This invention relates to the field of lithium-sulfur battery technology, specifically to a lithium-sulfur battery cathode material and its preparation method, as well as an all-solid-state lithium-sulfur battery. Background Technology

[0002] With the rise and development of drones, eVTOL, robots and new energy vehicles, the requirements for the safety and energy density of battery technology are becoming increasingly stringent. Traditional liquid lithium-ion batteries are increasingly unable to meet consumer needs, especially in terms of safety performance. The release of the new national standard in 2026 requires batteries to not catch fire or explode. Therefore, the development of high-energy-density and high-safety all-solid-state batteries has become the trend of future industry development.

[0003] As a promising next-generation high-performance battery, all-solid-state lithium-sulfur batteries have attracted increasing attention from researchers and companies due to their ultra-high energy density and high safety. Lithium-sulfur batteries use sulfur / lithium disulfide as the positive electrode and lithium as the negative electrode. Elemental sulfur has a theoretical specific capacity as high as 1675 mAh / g and is inexpensive and abundant. Although all-solid-state lithium-sulfur batteries do not suffer from the shuttle effect problem of liquid lithium-sulfur batteries, they also face significant challenges: sulfur and lithium disulfide are both insulators with poor ionic and electronic conductivity, making it difficult for sulfur to achieve its actual specific capacity; the slow redox kinetics between solid-phase sulfur and solid-phase lithium sulfide result in poor rate performance; the large volume change caused by the sulfur-lithium disulfide reaction leads to poor electrode stability and susceptibility to electrode pulverization, affecting the battery's cycle life; and the growth of lithium dendrites in the negative electrode poses a safety hazard of internal short circuits between the positive and negative electrodes. These challenges to the performance and safety of all-solid-state lithium-sulfur batteries hinder their commercial application.

[0004] To address the aforementioned issues, it is necessary to develop a lithium-sulfur battery cathode material and its preparation method, as well as an all-solid-state lithium-sulfur battery. Summary of the Invention

[0005] The purpose of this invention is to provide a lithium-sulfur battery cathode material and its preparation method, as well as an all-solid-state lithium-sulfur battery.

[0006] To address the aforementioned problems in the prior art, this invention provides a lithium-sulfur battery cathode material, its preparation method, and an all-solid-state lithium-sulfur battery.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On one hand, the present invention provides a lithium-sulfur battery cathode material, which is a composite material of sulfur-high halosulfide-carbon nanotube-graphene, and the raw materials for preparation include sulfur, high halosulfide, carbon nanotube and graphene in a weight ratio of 50~90:1~10:4~20:4~20.

[0008] Furthermore, the high-halogen sulfide includes Li 6-a PS 5-a X 1+a (X=F, Cl, Br; a=0~1), Li7P2-bS5I (b=0~1), Li 5.5 PS 4.5 F 0.5 Any one of Br.

[0009] Secondly, the present invention provides a method for preparing a lithium-sulfur battery cathode material, comprising the following steps: under an inert atmosphere, high-speed dispersion and uniform mixing of elemental sulfur and high-halogen sulfides, followed by the addition of carbon nanotubes and graphene for a second dispersion and mixing.

[0010] Furthermore, the high-speed dispersion rate is 1000~6000 rpm, and the dispersion time is 10~300 min; the second dispersion rate is 100~1000 rpm, and the dispersion time is 60~600 min.

[0011] Thirdly, the present invention also provides an all-solid-state lithium-sulfur battery, characterized in that the all-solid-state lithium-sulfur battery comprises a sulfur positive electrode, a solid electrolyte membrane, a conductive membrane, and a lithium negative electrode; the sulfur positive electrode contains a composite material of sulfur-high halosulfide-carbon nanotube-graphene and a binder, and is prepared by fiberization and dry electrode processes.

[0012] Furthermore, the weight ratio of the sulfur-high halosulfide-carbon nanotube-graphene composite material and the binder in the sulfur cathode is (90%~98%):(2%~10%); furthermore, the binder is any one of PTFE, PVDF, and gelatin-carbon composite system.

[0013] Furthermore, the solid electrolyte membrane comprises a solid electrolyte and a binder; the solid electrolyte comprises Li3PS4 and Li7P3S. 11 Li6PS5Cl, Li 5.5 PS 4.5 Cl 1.5 , Li7P2S8I, Li2S-B2S3-P2S5-LiI and Li 10 GeP2S 12The binder comprises any one or at least two of the following: PVDF, PEO, and PTFE; the thickness of the solid electrolyte membrane is 5-50 μm.

[0014] Furthermore, the conductive film is any one of carbonized film, carbon fiber-based composite film, carbon nanotube-based composite film, and PEDOT:PSS-based thin film, and the thickness of the conductive film ranges from 1 to 20 μm, and the porosity ranges from 10% to 80%.

[0015] Furthermore, the lithium anode is any one of metallic lithium, lithium-carbon alloy, or lithium-metal alloy, wherein the metal in the lithium-metal alloy includes at least one of Al, Sn, Mg, Zn, In, Ze, Ti, and Ag.

[0016] Furthermore, the preparation method of the all-solid-state lithium-sulfur battery is as follows: the sulfur positive electrode, solid electrolyte membrane, conductive membrane and lithium negative electrode are cut into specific shapes, and stacked in sequence with sulfur positive electrode-solid electrolyte membrane-conductive membrane-lithium negative electrode as the unit. They are then bonded together by isostatic pressing to form a bare cell, and after packaging, a solid-state battery can be obtained.

[0017] The beneficial effects of this invention are as follows: This invention provides a lithium-sulfur battery cathode material, its preparation method, and an all-solid-state lithium-sulfur battery. The lithium-sulfur battery cathode material is prepared by ultra-high-speed dispersion and mixing of elemental sulfur and a high-halogen sulfide electrolyte using a high-speed disperser. Under an inert atmosphere, a mechanochemical reaction causes halogen segregation to the surface of the elemental sulfur particles, forming a halogen-lithium compound interface coating layer, thereby improving the kinetics of lithium-ion transport and suppressing sulfur volume expansion. Carbon nanotubes and graphene are then added and dispersed using a ball mill to prepare a sulfur-high-halogen sulfide-carbon nanotube-graphene composite material. The carbon nanotubes and graphene construct a good three-dimensional electronic conductivity network, giving the composite material both good ionic and electronic conductivity. The sulfur cathode material prepared by the composite material and binder through fiberization and dry electrode processes has a controllable thickness and can be used to fabricate thick electrodes, loading more sulfur active materials, achieving a sulfur cathode with a capacity of 10 mAh / cm². 2 The above-mentioned high surface capacitance is achieved through a conductive film placed between the solid electrolyte membrane and the lithium anode. This film serves two purposes: firstly, it prevents direct contact between the electrolyte and lithium, avoiding side reactions that could lead to the loss of active lithium; secondly, its excellent conductivity provides space for lithium deposition during cycling, preventing the formation and growth of lithium dendrites that could cause internal short circuits, thus significantly improving battery life and safety. Furthermore, the materials used in this invention are readily available for large-scale production or have already been commercially applied, and the preparation method can be fully automated using existing equipment, making it suitable for large-scale industrial production. Attached Figure Description Figure 1 This is a schematic diagram of the internal structure of an all-solid-state lithium-sulfur battery. Among them, 1-sulfur cathode, 2-solid electrolyte membrane, 3-conductive membrane, and 4-lithium anode. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific embodiments will be used for further illustration below.

[0019] Example 1 like Figure 1 As shown, in this embodiment 1, an all-solid-state lithium-sulfur battery includes a sulfur positive electrode 1, a solid electrolyte membrane 2, a conductive membrane 3, and a lithium negative electrode 4. The preparation method of all-solid-state lithium-sulfur batteries is as follows: (1) Preparation of sulfur cathode composite material: Under an inert argon atmosphere, elemental sulfur is reacted with high-halogen sulfides Li 5.5 PS 4.5 Cl 1.5 Sulfur-high halogen sulfide composite material was obtained by high-speed dispersion and mixing in a high-speed mixer at a mass ratio of 70:10. The dispersion speed was 3000 rpm and the dispersion time was 60 min. Cooling water was circulated during the dispersion process to keep the maximum temperature below 60℃. Under the protection of an inert argon atmosphere, the well-mixed sulfur-high halogen sulfide composite material was mixed with carbon nanotubes and graphene in a mass ratio of 80:10:10 and added to a high-energy ball mill. The dispersion speed was adjusted to 500 rpm and the ball milling time was 300 min. After thorough dispersion and uniform mixing, a sulfur-high halogen sulfide-carbon nanotube-graphene sulfur cathode composite material was obtained.

[0020] (2) Preparation of sulfur positive electrode sheet: In a drying chamber, the above-mentioned sulfur-high halogen sulfide-carbon nanotube-graphene composite material and binder PTFE are mixed at a mass ratio of 95:5 in a high-speed mixer at a speed of 2000 rpm for 60 min and then the PTFE is fiberized at a high speed of 6000 rpm for 30 min. The resulting uniformly mixed dry powder is pressed into a film by a dry electrode process using multi-stage rollers with 10T pressure. The film is then rolled up to be heated at 80℃ and pressed onto both sides of an aluminum foil with 0.6T pressure. Finally, it is pressed with 50T pressure to obtain a sulfur positive electrode sheet.

[0021] (3) Preparation of solid electrolyte membrane: Under an inert atmosphere, sulfide electrolytes Li2S-B2S3-P2S5-LiI and PTFE were mixed at a mass ratio of 95:5 in a high-speed mixer at a speed of 2000 rpm for 30 min and then the PTFE was fiberized at a high speed of 6000 rpm for 15 min. The resulting uniformly mixed dry powder was repeatedly pressed into thin sheets by a dry electrode process using multi-stage rollers with 10T pressure to obtain a solid electrolyte membrane with a thickness of 15 μm.

[0022] (4) Preparation of lithium anode sheet: In a drying room or under a protective drying atmosphere, lithium-carbon alloy strips and carbon-coated copper foils are hot-pressed and bonded together under the conditions of a roller temperature of 80°C and a pressure of 80 MPa to obtain lithium-copper composite strips. The thickness of the lithium alloy layer on one side after bonding is 50 μm. A 10 μm thick carbonized film is attached to one side of the lithium alloy layer of the lithium-copper composite strip. After cutting, lithium negative electrode sheets with carbonized film protection are obtained.

[0023] (5) Fabrication and testing of pouch-type all-solid-state batteries: In a drying chamber, the sulfur positive electrode, solid electrolyte membrane, and lithium negative electrode protected by a carbide film are stacked sequentially. A schematic diagram of the internal structure of the battery cell is shown below. Figure 1 As shown, hot pressing and shaping were performed at 80°C under a pressure of 500 MPa, and the cells were stacked and assembled into a soft-pack all-solid-state battery with a designed capacity of 10 Ah. After cold isostatic pressing, room temperature testing was performed using a fixture under a pressure of 5 MPa.

[0024] The test method is as follows: (1) High-rate discharge test: After the battery is tested for 1C discharge capacity, the battery is fully charged to 3.0V at 1C rate, left to stand for 30 minutes, and then discharged to 1.5V at 4C high rate. The 4C discharge capacity is compared with the 1C discharge capacity to obtain the high-rate discharge capacity retention rate. (2) Cyclic endurance test: The battery is discharged to 1.5V at 0.3C in the first week and then charged to 3.0V. A long cycle test of 1C discharge / 1C charge is carried out, with a voltage cutoff range of 1.8V to 2.8V. (3) Needle penetration safety test: After the battery is charged to 3.0V at a rate of 0.3C, a steel needle with a diameter of 3mm and a taper of 45° is used to penetrate the center of the cell vertically at a speed of 0.1mm / s for 1 hour. The cell is observed to see if it catches fire or explodes. The number of cell samples is 3pcs.

[0025] The test results show that (1) the discharge capacity retention rate of the battery cell at 4C high rate is 90% (relative to the discharge capacity at 1C rate), which reflects excellent rate performance. (2) After 500 cycles of 1C discharge / 1C charge long cycle test, the battery capacity retention rate is 92.5%, which reflects good cycle stability. (3) The needle penetration safety test results show that none of the 3 cells caught fire or exploded, and the test pass rate is 100%, which reflects excellent safety performance.

[0026] Example 2 This embodiment is basically the same as Embodiment 1, except that the high-halogen sulfide electrolyte Li in the sulfur cathode composite material is different. 5.5 PS 4.5 Cl 1.5 Replace with Li 5.5 PS 4.5 F 0.5 Br.

[0027] Example 3 This embodiment is basically the same as Embodiment 1, except that the high-halogen sulfide electrolyte Li in the sulfur cathode composite material is different. 5.5 PS 4.5 Cl 1.5 Replace it with Li7PS5I.

[0028] Example 4 This embodiment is basically the same as Embodiment 1, except that the dispersion speed and time of the high-speed mixer in the sulfur cathode composite material preparation method are adjusted to 2000 rpm and 120 min.

[0029] Example 5 This embodiment is basically the same as Embodiment 1, except that the rotation speed and time of the high-energy ball mill in the sulfur cathode composite material preparation method are adjusted to 1000 rpm and 60 min, respectively.

[0030] Example 6 This embodiment is basically the same as Embodiment 1, except that: elemental sulfur and high-halogen sulfide Li are present in the sulfur cathode composite material. 5.5 PS 4.5 Cl 1.5 The ratio of carbon nanotubes to graphene was adjusted to 90:2:4:4.

[0031] Example 7 This embodiment is basically the same as Embodiment 1, except that: elemental sulfur and high-halogen sulfide Li are present in the sulfur cathode composite material. 5.5 PS 4.5 Cl 1.5 The ratio of carbon nanotubes to graphene was adjusted to 50:10:20:20.

[0032] Example 8 This embodiment is basically the same as Embodiment 1, except that the ratio of the composite material to the binder PTFE in the sulfur cathode is adjusted to 90:10.

[0033] Example 9 This embodiment is basically the same as Embodiment 1, except that the binder PTFE in the sulfur cathode is replaced with PVDF.

[0034] Example 10 This embodiment is basically the same as Embodiment 1, except that the sulfide electrolyte Li2S-B2S3-P2S5-LiI in the solid electrolyte membrane is replaced with Li 5.5 PS 4.5 Cl 1.5 .

[0035] Example 11 This embodiment is basically the same as Embodiment 1, except that the carbonized film on the surface of the lithium anode is replaced with a carbon fiber-based composite film.

[0036] Example 12 This embodiment is basically the same as Embodiment 1, except that the carbonized film on the surface of the lithium anode is replaced with a PEDOT:PSS-based thin film.

[0037] Example 13 This embodiment is basically the same as Embodiment 1, except that the thickness of the carbonized film on the lithium anode surface is adjusted to 5 μm.

[0038] Example 14 This embodiment is basically the same as Embodiment 1, except that the lithium-carbon alloy in the lithium anode is replaced with metallic lithium.

[0039] Comparative Example 1 This embodiment is basically the same as Embodiment 1, except that: there is no sulfur cathode composite material preparation process; instead, in the sulfur cathode preparation process, elemental sulfur and high-halogen sulfide Li are directly added in the same proportion as in Embodiment 1. 5.5 PS 4.5 Cl 1.5 Carbon nanotubes, graphene, and PTFE binder are mixed and fiberized at high speed in a high-speed mixer under the same process conditions. The mixture is then pressed into a film using a dry electrode process, thermally bonded to aluminum foil, and finally pressed by a 50T pressure roller to obtain a sulfur positive electrode sheet.

[0040] Comparative Example 2 This embodiment is basically the same as Embodiment 1, except that the carbonization film is removed and no treatment is done on the surface of the lithium anode.

[0041] Comparative Example 3 This embodiment is basically the same as Embodiment 1, except that: there is no solid electrolyte membrane, the sulfur positive electrode and the lithium negative electrode are separated by a PE separator of the same thickness of 15μm, and the electrolyte 1 M LiTFSI / DOL:DME (1:1)+1%LiNO3 is injected and the liquid soft pack battery is assembled by stacking the same process.

[0042] Batteries for each embodiment and comparative example were prepared according to the above method, and various performance parameters were measured. The results are shown in the table below.

[0043] Table 1

[0044] From the data in the table above, we can see that: The all-solid-state lithium-sulfur batteries of the various embodiments of this application not only have better rate performance and cycle performance, but also have better energy density and safety performance than liquid lithium-sulfur batteries, and have excellent overall performance.

[0045] Comparing Examples 1 and 2-3, it can be seen that switching the type of high-halogen sulfide has little impact on battery performance. This may be because different high-halogen sulfides and elemental sulfur have the same reaction mechanism under high-speed dispersion, that is, under an inert atmosphere, halogens segregate to the surface of elemental sulfur particles through mechanochemical reactions, forming a halogen-lithium compound interface coating layer, thereby improving the kinetics of lithium-ion transport and suppressing sulfur volume expansion, thus improving the rate capability and cycle stability of lithium-sulfur batteries.

[0046] Comparing Examples 1 and 4, it can be seen that the dispersion process of the high-speed disperser has a certain impact on the performance of the sulfur-high-halogen sulfide composite material. Appropriate dispersion speed and dispersion time can make halogens more uniformly segregate to the surface of elemental sulfur particles, forming a uniform halogen-lithium compound coating layer, thereby obtaining a composite material with better ion dynamics performance.

[0047] Comparing Examples 1 and 5, it can be seen that the mixing process of the high-energy ball mill has a certain impact on the performance of the sulfur-high-halogen sulfide-carbon nanotube-graphene composite material. Appropriate rotation speed and mixing time can make the carbon nanotubes and graphene mixed more fully and uniformly with the sulfur-high-halogen sulfide composite material, thereby building a better three-dimensional conductive network and a composite material with better electron dynamics performance.

[0048] Comparing Examples 1 and 6-7, it can be seen that the proportion of each component in the sulfur-high halosulfide-carbon nanotube-graphene composite material affects the battery performance. In Example 6, the proportion of high halosulfide and carbon nanotube-graphene is relatively low, so the overall conductivity of the composite material is affected to a certain extent. In terms of battery performance, the rate performance and cycle performance are worse than those of Example 1. In Example 7, the proportion of high halosulfide and carbon nanotube-graphene is relatively high, so the overall conductivity of the composite material is better, and the rate performance is better than that of Example 1. However, the high content of carbon nanotubes and graphene may pose a risk of particle agglomeration and uneven dispersion, which is not conducive to cycle stability. Therefore, the appropriate proportion of each component is a key factor in the performance of the composite material.

[0049] Comparing Examples 1 and 8, it can be seen that the ratio of composite material to binder in sulfur cathode has a certain impact on battery performance. After the binder content is adjusted from 5% to 10%, the conductivity of sulfur cathode will be affected to a certain extent, thus the rate performance of the battery will deteriorate, but the impact on the cycle performance of the battery is small.

[0050] Comparing Examples 1 and 9, it can be seen that the type of binder in the sulfur cathode has an impact on battery performance. In the dry electrode process, PTFE is more conducive to the uniform dispersion and fiberization of sulfur composite materials than PVDF, so the rate performance and cycle performance of the battery will be better.

[0051] Comparing Examples 1 and 10, it can be seen that the type of solid electrolyte has a certain impact on battery performance. The electrolyte Li2S-B2S3-P2S5-LiI has a better effect than Li... 5.5 PS 4.5 Cl 1.5 It is more compatible with sulfur cathodes and lithium anodes, and has a certain inhibitory effect on interfacial side reactions, thus exhibiting better cycle stability.

[0052] Comparing Examples 1 and 11-12, it can be seen that the type of conductive film on the lithium anode surface affects battery performance. Carbonized film, carbon fiber-based composite film, and PEDOT:PSS-based film have different effects on lithium-ion deposition and electronic conductivity due to their different conductivity and microstructure. Carbonized film with good electronic conductivity, microscopic three-dimensional conductive network structure, and suitable porosity is conducive to uniform lithium-ion deposition and rapid electron conduction, thus the rate performance and cycle performance of the battery will be better.

[0053] Comparing Example 1 and Example 13, it can be seen that the change in the thickness of the carbonized film has little effect on the rate performance of the battery. However, a thinner carbonized film provides limited space for lithium deposition, which is not conducive to long-term cycle stability. Therefore, a suitable carbonized film thickness is more beneficial to the battery's durability.

[0054] Comparing Examples 1 and 14, it can be seen that the lithium-carbon alloy anode exhibits better cycle stability than the metallic lithium anode. This may be related to the more robust structure and chemical stability of the lithium-carbon alloy, which is more conducive to uniform lithium deposition and suppression of interfacial side reactions.

[0055] Comparing Example 1 and Comparative Example 1, it can be seen that the sulfur cathode composite material prepared by the present invention exhibits superior performance compared to a simple mixture of the various substances. This is mainly because, through the preparation of the composite material of the present invention, high-halogen sulfides cause halogen segregation to the surface of elemental sulfur particles via mechanochemical reactions, forming a halogen-lithium compound interface coating layer, thereby improving the kinetics of lithium-ion transport and suppressing sulfur volume expansion. Furthermore, the carbon nanotubes and graphene, after being mixed through ball milling, are more uniform, constructing a well-developed three-dimensional conductive network. Therefore, the lithium-sulfur battery using this composite material will have better rate performance and cycle performance.

[0056] Comparing Example 1 and Comparative Example 2, it can be seen that removing the carbon film on the surface of the lithium anode has virtually no impact on the battery's rate performance, but it will affect the battery's cycle stability to some extent. This is because the presence of the carbon film, on the one hand, avoids the side reactions caused by direct contact between the electrolyte and lithium, which would result in the loss of active lithium; on the other hand, its good conductivity provides space for lithium deposition during cycling, avoiding the formation and growth of lithium dendrites that could cause internal short circuits, thereby greatly improving the battery's lifespan.

[0057] Comparing Example 1 and Comparative Example 3, it can be seen that the all-solid-state lithium-sulfur battery has better cycle performance and safety performance than the liquid lithium-sulfur battery. This is because the liquid lithium-sulfur battery has the problem of the shuttle effect of intermediate polysulfide products in the liquid electrolyte, and the polysulfides react and deposit on the surface of the negative electrode. The all-solid-state lithium-sulfur battery does not have this problem, so its cycle performance is better. Because the electrolyte of the liquid lithium-sulfur battery is flammable, it is very easy for the battery to undergo thermal runaway due to short circuit and combustion during the nail penetration test. Therefore, its safety performance is not as good as that of the all-solid-state lithium-sulfur battery.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention; those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention; and all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A lithium-sulfur battery cathode material, characterized in that, The lithium-sulfur battery cathode material is a composite material of sulfur-high halogen sulfide-carbon nanotube-graphene, and the raw materials for preparation include sulfur, high halogen sulfide, carbon nanotube and graphene in a weight ratio of 50~90:1~10:4~20:4~20.

2. The lithium-sulfur battery cathode material according to claim 1, characterized in that, The high-halogen sulfides include Li 6-a PS 5-a X 1+a (X=F, Cl, Br; a=0~1), Li7P2-bS5I (b=0~1), Li 5.5 PS 4.5 F 0.5 Any one of Br.

3. A method for preparing the lithium-sulfur battery cathode material according to claim 1 or 2, characterized in that the step include: The mixture is prepared by high-speed dispersion and uniform mixing of elemental sulfur and high-halogen sulfides under an inert atmosphere, followed by the addition of carbon nanotubes and graphene for a second dispersion and mixing.

4. The method for preparing the lithium-sulfur battery cathode material according to claim 3, characterized in that, The high-speed dispersion rate is 1000~6000 rpm, and the dispersion time is 10~300 min; the second dispersion rate is 100~1000 rpm, and the dispersion time is 60~600 min.

5. An all-solid-state lithium-sulfur battery, characterized in that, The all-solid-state lithium-sulfur battery includes a sulfur cathode, a solid electrolyte membrane, a conductive membrane, and a lithium anode; the sulfur cathode contains a composite material of sulfur-high halogen sulfide-carbon nanotube-graphene and a binder, and is prepared by fiberization and dry electrode processes.

6. The all-solid-state lithium-sulfur battery according to claim 5, characterized in that, The weight ratio of the sulfur-high halide-carbon nanotube-graphene composite material and the binder in the sulfur cathode is (90%~98%):(2%~10%), and the binder is any one of PTFE, PVDF, and gelatin-carbon composite system.

7. The all-solid-state lithium-sulfur battery according to claim 5, characterized in that, The solid electrolyte membrane comprises a solid electrolyte and a binder; the solid electrolyte comprises Li3PS4 and Li7P3S4. 11 Li6PS5Cl, Li 5.5 PS 4.5 Cl 1.5 , Li7P2S8I, Li2S-B2S3-P2S5-LiI and Li 10 GeP2S 12 The binder comprises any one or at least two of the following: PVDF, PEO, and PTFE; the thickness of the solid electrolyte membrane is 5-50 μm.

8. The all-solid-state lithium-sulfur battery according to claim 5, characterized in that, The conductive film is any one of carbonized film, carbon fiber-based composite film, carbon nanotube-based composite film, and PEDOT:PSS-based thin film. The thickness of the conductive film ranges from 1 to 20 μm, and the porosity ranges from 10% to 80%.

9. The all-solid-state lithium-sulfur battery according to claim 5, characterized in that, The lithium anode is any one of metallic lithium, lithium-carbon alloy, or lithium-metal alloy, wherein the metal in the lithium-metal alloy includes at least one of Al, Sn, Mg, Zn, In, Ze, Ti, and Ag.

10. The all-solid-state lithium-sulfur battery according to any one of claims 5 to 9, characterized in that, The method for preparing the all-solid-state lithium-sulfur battery is as follows: sulfur cathode, solid electrolyte membrane, conductive membrane and lithium anode are cut and stacked in sequence in the form of sulfur cathode-solid electrolyte membrane-conductive membrane-lithium anode, and bonded together by isostatic pressing to form a bare cell, and then packaged to obtain a solid-state battery.

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