A battery-grade lithium sulfide material, a preparation method and application thereof

Abstract

The application belongs to the technical field of rechargeable batteries, and discloses a battery-grade lithium sulfide material and a preparation method and application thereof. A sulfur source lithium source integrated compound or a mixture of a sulfur source lithium source integrated compound and a catalyst is mechanically ball milled to obtain raw material fine powder; the raw material fine powder is filled into a specific reaction container, high-temperature calcination is carried out under pure hydrogen or hydrogen atmosphere with inert gas as a carrier gas to obtain a solid product, and the solid product is collected under inert atmosphere protection, so that lithium sulfide or a lithium sulfide-catalyst composite material is obtained. The lithium sulfide prepared by the application can be used in lithium-sulfur batteries or sulfide solid electrolytes, and the lithium sulfide-catalyst composite material can be used in lithium-sulfur batteries. The process flow of the application is simple to operate, does not need to use organic solvents for secondary purification and impurity removal, and the like, product collection is simple, by-product water vapor is clean, there is no carbon emission in the reaction process, the application conforms to the green chemistry concept, and is easy to realize industrialized production and has high economic value.

Description

Technical Field

[0001] This invention belongs to the field of rechargeable battery technology, specifically, it relates to a battery-grade lithium sulfide material, its preparation method, and its application. Background Technology

[0002] With the rapid development of science and technology, electronic products, electric vehicles, and other devices are demanding increasingly higher energy density from their power systems. However, due to limitations in theoretical capacity, it is difficult to improve the energy density of lithium-ion batteries. Therefore, there is a need to develop new battery systems with higher energy density, longer cycle life, and greater environmental friendliness to meet the urgent demand of modern society for high-performance energy storage systems. The energy density of lithium-sulfur batteries (2600Wh / kg) is... -1 The abundant reserves, low price, and low toxicity of sulfur in lithium-sulfur batteries give them a promising future. Compared to sulfur cathodes, Li₂S is fully lithiated, making it easier to address volume expansion issues. Furthermore, it can be paired with lithium-free anodes (such as silicon and tin), avoiding the safety concerns associated with stringent manufacturing processes associated with lithium metal anodes. In addition, lithium sulfide is a key raw material for sulfide solid-state electrolytes, with significant future demand in solid-state batteries. Sulfide solid-state electrolytes possess high ionic conductivity and ease of processing, allowing for close contact with active materials through cold pressing to achieve low interfacial resistance. This makes them highly suitable for electric vehicle power batteries and a promising future technology. However, sulfide electrolytes are currently expensive (over 100,000 RMB per kilogram), primarily due to the difficulty and high price (over 20,000 RMB per kilogram) of large-scale production of its raw material, Li₂S. Therefore, low-cost, large-scale production of Li₂S remains a major challenge for the industry. Consequently, lithium sulfide, a crucial battery material, has attracted considerable attention.

[0003] Currently, the main methods for preparing Li2S can be divided into carbothermal reduction, ball milling, metallothermal reduction, and liquid phase methods.

[0004] Carbothermic reduction refers to the method of reducing lithium- and sulfur-containing compounds with a carbon source at high temperatures to obtain Li₂S. It is one of the current industrial methods for producing Li₂S. The required lithium- and sulfur-containing precursors are Li₂SO₄, while the carbon source can be polyvinylpyrrolidone, glucose, sucrose, graphene, etc. Representative patents include CN110112390A, CN114275742A, CN108400327A, and CN108258222A. However, this method is energy-intensive and costly, and especially produces a large amount of the greenhouse gas CO₂, which does not conform to the principles of green chemistry.

[0005] The principle of ball milling is to mechanically ball-mill a mixture of elemental sulfur / sulfur compounds and metallic lithium / lithium compounds in an inert atmosphere to obtain lithium sulfide. Representative patents include CN112777571A and CN108336400A. This method is simple to operate and has no carbon emissions. However, it requires frequent loading and unloading, has low product purity, high requirements for ball milling equipment, consumes a lot of energy, and is not easy to scale up for production.

[0006] The metallothermic reduction method prepares lithium sulfide by mixing a reducing elemental metal and a lithium source compound in a specific ratio, followed by high-temperature calcination. Examples include magnesium metal and lithium sulfate, and aluminum metal and lithium sulfide. Representative patents include CN114477099A and CN115947313A. This method has advantages such as low preparation temperature, short reaction time, and no carbon emissions. However, the reaction is highly exothermic and excessively vigorous, posing safety risks.

[0007] The principle of the liquid-phase method is to react elemental lithium or lithium-containing compounds with elemental sulfur or sulfur-containing compounds in a solvent phase to prepare lithium sulfide. Representative patents include CN111517288A and CN109244383A. This method can prepare lithium sulfide at low temperatures, reducing energy consumption and eliminating carbon emissions. However, this reaction requires the consumption of organic solvents (ethanol, tetrahydrofuran, ethyl acetate, etc.), which are difficult to recycle and cause environmental pollution.

[0008] In summary, the preparation methods for lithium sulfide still have many problems, resulting in high costs and difficulties in industrialization. Therefore, finding a clean, simple, low-cost, and environmentally friendly preparation method is of profound significance. Summary of the Invention

[0009] One of the objectives of this invention is to provide a method for preparing battery-grade lithium sulfide materials, which has the advantages of being green and environmentally friendly, simple to operate and easy to industrialize, and is in line with the concept of green chemistry.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A method for preparing battery-grade lithium sulfide material includes:

[0012] S1. The raw material fine powder is obtained by mechanically ball milling a sulfur-lithium source integrated compound or a mixture of a sulfur-lithium source integrated compound and a catalyst.

[0013] S2. The raw material powder is filled into a reaction vessel, and the raw material powder is calcined at high temperature under pure hydrogen or hydrogen atmosphere with an inert gas as the carrier gas to obtain a solid product.

[0014] S3. Collect the solid product under an inert atmosphere to obtain lithium sulfide or lithium sulfide-catalyst composite material.

[0015] The reaction vessel is made of one of the following materials: graphite, metal, metal alloy, and metal oxide, such as nickel, molybdenum, and quartz.

[0016] The reaction vessel is either a crucible-shaped reaction vessel or a cap-type reaction vessel. The crucible-shaped reaction vessel utilizes the reflection of airflow from its bottom surface to ensure sufficient contact between the reactant gas and the reactants; the cap-type reaction vessel utilizes airflow passing through the vessel to ensure sufficient contact between the reactant gas and the reactants.

[0017] The reaction equation for high-temperature calcination is as follows:

[0018] 4H₂ + Li₂SO₄ → Li₂S + 4H₂O

[0019] H2+MSO4→MS+H2O (M=Co, Ni, Zn, etc.)

[0020] H2+M x O y → M + H₂O (M = Co, Ni, Cu, etc.)

[0021] In some embodiments, the integrated sulfur and lithium source compound is lithium sulfate.

[0022] In some embodiments, the catalyst precursor is an aqueous or anhydrous metal sulfate, or an aqueous or anhydrous metal oxide.

[0023] Preferably, the aqueous or anhydrous metal sulfate is one of cobalt sulfate, nickel sulfate, and zinc sulfate.

[0024] Preferably, the aqueous or anhydrous metal oxide is one of cobalt tetroxide, nickel oxide, and copper oxide.

[0025] In some embodiments, the mass ratio of the integrated sulfur-lithium source compound to the catalyst precursor is 10:1 to 20:1.

[0026] In some embodiments, the hydrogen atmosphere with an inert gas as the carrier gas is one of a hydrogen-argon mixture, a hydrogen-nitrogen mixture, or a hydrogen-helium mixture.

[0027] In some embodiments, the cap-type reaction vessel includes a cap bottom, a cap top, and a vent pipe; both the cap bottom and the cap top have cavities inside, and each is open at one end and semi-closed at the other end due to communication with the vent pipe; the cap top is disposed inside the cap bottom and forms a wedge connection with the cap bottom, wherein the open end of the cap top is opposite to the semi-closed end of the cap bottom; the vent pipe has a necking near the cap bottom and the cap top, and quartz wool is placed in the section of the pipe between the necking and the cap bottom and the cap top.

[0028] In some implementations, the reaction vessel is made of graphite or corundum alumina, which can ensure that the solid product does not stick to the reaction vessel.

[0029] In some implementations, the high-temperature calcination temperature is 700-900°C and the time is 8-20 hours.

[0030] The second objective of this invention is to provide a battery-grade lithium sulfide material, which is prepared by the above-described method to obtain lithium sulfide or lithium sulfide-catalyst composite material.

[0031] The third objective of this invention is to provide an application of a battery-grade lithium sulfide material, wherein the lithium sulfide is used in lithium-sulfur batteries or sulfide solid electrolytes, and the lithium sulfide-catalyst composite material is used in lithium-sulfur batteries.

[0032] The beneficial effects of this invention are:

[0033] This invention employs a crucible-shaped or cap-type reaction vessel made of a specific material to hold the fine powdered raw materials, thereby increasing the contact area between hydrogen and lithium sulfate. This avoids the difficulties encountered with traditional ceramic boat-shaped containers, where insufficient gas-solid contact leads to incomplete reactions and the presence of impurities. The preparation method provided by this invention is simple, requiring no secondary purification steps using organic solvents. It uses lithium sulfate, lithium sulfate, and catalyst precursors as raw materials, and the hydrogen gas is widely available. Furthermore, product collection is simple, and the byproduct water vapor is clean. The water vapor can be recovered and recycled to produce hydrogen through water electrolysis. The reaction process produces no carbon emissions, avoiding the introduction of greenhouse gases due to carbon, aligning with green chemistry principles, and is more suitable for large-scale industrial production, thus possessing high economic value.

[0034] The lithium sulfide product or lithium sulfide-catalyst composite material obtained by the above preparation method is clean, pure, and suitable for application in the battery manufacturing field. The lithium sulfide product prepared by this invention can be directly used as a raw material for lithium-sulfur batteries and sulfide solid electrolytes; the prepared lithium sulfide-catalyst composite material has good conductivity, high discharge capacity, and excellent rate performance, showing good application potential in the field of lithium-sulfur batteries. Attached Figure Description

[0035] Figure 1 This is a flowchart illustrating the preparation of battery-grade lithium sulfide materials according to the present invention;

[0036] Figure 2 This is a schematic diagram showing the structure and usage of the crucible-shaped reaction vessel used in the preparation of battery-grade lithium sulfide materials according to the present invention.

[0037] Among them: 1. Quartz tube, 2. Flange, 3. Inlet pipe, 4. Outlet pipe, 5. Raw material fine powder, 6. Crucible-shaped reaction vessel;

[0038] Figure 3 This is a schematic diagram of the structure and usage of the cap-type reaction vessel used in the preparation of battery-grade lithium sulfide materials according to the present invention.

[0039] Among them: 1. Quartz tube, 2. Flange, 3. Inlet pipe, 4. Outlet pipe, 5. Raw material fine powder, 7. Cap-type reaction vessel, 701. Cap bottom, 702. Cap top, 703. Neck, 704. Vent pipe, 8. Quartz wool, 9. Connecting hose, 10. Needle valve.

[0040] Figure 4 The image shows the XRD pattern of lithium sulfide prepared in Example 1 of this invention.

[0041] Figure 5 The XRD pattern of lithium sulfide prepared in Example 2 of this invention;

[0042] Figure 6 The XRD pattern of lithium sulfide prepared in Example 3 of this invention;

[0043] Figure 7 Raman spectra of lithium sulfide prepared in Example 3 of this invention and commercial lithium sulfide;

[0044] Figure 8 SEM image of lithium sulfide prepared in Example 3 of the present invention;

[0045] Figure 9 The XRD pattern of the lithium sulfide-nickel composite material prepared in Example 4 of the present invention;

[0046] Figure 10 The XRD pattern of the lithium sulfide-cobalt sulfide composite material prepared in Example 5 of the present invention;

[0047] Figure 11 The graph shows the 0.5C cycling performance of lithium sulfide-catalyst composite material prepared in Example 5 of the present invention compared with that of lithium sulfide prepared in Example 3;

[0048] Figure 12 The graph shows the 0.5C cycling performance of lithium sulfide prepared in Example 3 of the present invention compared with that of commercial lithium sulfide.

[0049] Figure 13 The cycling performance of a ternary cathode lithium battery assembled with a solid electrolyte and prepared using lithium sulfide prepared in Example 3 of the present invention is compared with that prepared using commercial lithium sulfide. Detailed Implementation

[0050] To make the solutions and advantages of the present invention clearer, the present invention and its advantages will be described in detail below with reference to specific embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0051] This invention provides a method for preparing battery-grade lithium sulfide material, comprising:

[0052] The raw material fine powder is obtained by mechanically ball milling a compound containing both sulfur and lithium sources, or a mixture of a compound containing both sulfur and lithium sources and a catalyst.

[0053] The fine powder of the raw material is filled into a reaction vessel, and the fine powder of the raw material is calcined at high temperature under pure hydrogen or hydrogen atmosphere with an inert gas as the carrier gas to obtain a solid product.

[0054] The reaction vessel is a crucible-shaped reaction vessel or a cap-type reaction vessel, and the material is one of graphite, metal, metal alloy, and metal oxide.

[0055] The solid product is collected under an inert atmosphere to obtain lithium sulfide or lithium sulfide-catalyst composite material.

[0056] Figure 1 The process flow of the above preparation method is shown. This method can directly prepare lithium sulfide or lithium sulfide-catalyst composite material. The entire preparation process generates no waste, is clean and hygienic, does not require a post-purification step, has a simple process, low equipment requirements, is suitable for large-scale industrial production, conforms to the concept of green chemistry, and has good economic benefits.

[0057] It should be noted that, compared with existing technologies, the preparation method and products provided by this invention are of positive significance for promoting the early mass production of lithium-sulfur batteries and their application in new energy vehicles.

[0058] The sulfur-lithium source integrated compound described in this invention refers to a compound that simultaneously contains lithium and sulfur elements.

[0059] In some embodiments, the integrated sulfur and lithium source compound is lithium sulfate, and the high-temperature reaction between hydrogen and lithium sulfate is: 4H2 + Li2SO4 → Li2S + 4H2O.

[0060] like Figure 2 As shown, the specific operation of filling the fine raw material powder 5 into the crucible-shaped reaction vessel 6 and calcining it at high temperature under a pure hydrogen atmosphere or a hydrogen atmosphere with an inert gas as the carrier gas is as follows:

[0061] The fine powder 5 of the raw material is placed into a crucible-shaped reaction vessel 6, which is then placed inside a quartz tube 1. Both ends of the quartz tube 1 are connected to an inlet pipe 3 and an outlet pipe 4 via flanges 2, respectively. The open end of the crucible-shaped reaction vessel 6 faces the inlet pipe 3. Pure hydrogen or hydrogen with an inert gas as the carrier gas is introduced through the inlet pipe 3, and the air inside the quartz tube 1 is purged through the outlet pipe 4. The heating temperature of the tube furnace is then set for heating.

[0062] like Figure 3 As shown, the cap-type reaction vessel 7 of the present invention includes a cap bottom 701, a cap top 702, and a vent pipe 704, wherein the cap bottom 701, cap top 702, and vent pipe 704 are made of the same material.

[0063] The cap bottom 701 has a cylindrical external structure and an internal cavity. One end is open, while the other end is semi-closed due to its connection with the vent pipe 704. The inner diameter of the cap bottom 701 gradually increases from the semi-closed end to the open end, and the inner rotating surface has an inclined transition. The vent pipe 704 has a neck 703 near the cap bottom 701, and quartz wool 8 is placed in the section of the pipe between the neck 703 and the cap bottom 701. Both the neck 703 and the quartz wool 8 are used to prevent the raw material fine powder 5 from spilling out.

[0064] The cap top 702 has a frustum-shaped external structure with an internal cavity. One end is open, while the other end is semi-closed due to its connection with the vent pipe 704. The outer diameter of the cap top 702 gradually decreases from the semi-closed end to the open end, and the outer rotating surface has an inclined transition. A neck 703 is provided on the vent pipe 704 near the cap top 702, and quartz wool 8 is placed in the section of the pipe between the neck 703 and the cap top 702. Both the neck 703 and the quartz wool 8 are used to prevent the raw material fine powder 5 from spilling out.

[0065] The inner rotating surface of the cap bottom 701 and the outer rotating surface of the cap top 702 have the same inclination, which allows the cap bottom 701 and the cap top 702 to be connected by a wedge key, and the connection interface fits tightly.

[0066] The specific operation of filling the raw material fine powder 5 into the cap-type reaction vessel 7 and calcining it at high temperature under a pure hydrogen atmosphere or a hydrogen atmosphere with an inert gas as the carrier gas is as follows:

[0067] Quartz wool 8 is pre-placed inside the venting tube 704, and the two venting tubes 704 are respectively connected to the semi-closed ends of the cap bottom 701 and cap top 702. The raw material fine powder 5 is placed into the cavity of the cap top 702, and then the cap top 702 is inserted into the cap bottom 701 via a wedge connection. During insertion, it is pushed in and rotated at a certain angle, so that the outer rotating surface of the cap top 702 and the inner rotating surface of the cap bottom 701 form a tight fit, achieving the purpose of transmitting force and torque.

[0068] Next, the capped reaction vessel 7 is placed inside the quartz tube 1. Both ends of the quartz tube 1 are connected to vent pipes 704 via flanges 2, with the open end of the cap 702 facing the inlet pipe 3. The two vent pipes 704 are connected to the inlet pipe 3 and the outlet pipe 4 via flexible hoses 9, respectively. Needle valves 10 are installed on both the inlet pipe 3 and the outlet pipe 4 to control the gas flow rate. Pure hydrogen or hydrogen with an inert gas carrier is introduced through the inlet pipe 3, and after the air inside the quartz tube 1 is purged through the outlet pipe 4, the heating temperature of the tube furnace is set for heating.

[0069] In some embodiments, the catalyst precursor is an aqueous or anhydrous metal sulfate; preferably cobalt sulfate, nickel sulfate, or zinc sulfate.

[0070] In some embodiments, the catalyst precursor is an aqueous or anhydrous metal oxide; preferably, it is one of cobalt tetroxide, nickel oxide, or copper oxide.

[0071] In some embodiments, the mass ratio of the integrated sulfur-lithium source compound to the catalyst precursor is 10:1 to 20:1.

[0072] In some implementations, the mechanical ball milling method is planetary or high-energy vibration, the ball-to-material ratio is 30:1-4:1, and the milling time is 1-20 hours.

[0073] In some embodiments, the hydrogen atmosphere with an inert gas as the carrier gas can be a hydrogen-argon mixture, a hydrogen-nitrogen mixture, or a hydrogen-helium mixture.

[0074] In some implementations, the reaction vessel is made of graphite or corundum alumina, which can ensure that the solid product does not stick to the reaction vessel.

[0075] In some embodiments, the high-temperature calcination temperature is 700-900℃ and the time is 8-20h; the calcination equipment is a high-temperature tube furnace with a heating rate of 1-5℃ / min.

[0076] Example 1

[0077] A method for preparing battery-grade lithium sulfide material includes the following steps:

[0078] S1. Weigh 0.5g of anhydrous lithium sulfate and mechanically ball-mill it at 1700r / min for 1h to obtain fine powder of the raw material.

[0079] S2. Under the protection of a hydrogen-nitrogen mixture (75% H2), the fine powder of the raw material is filled into a crucible-shaped reaction vessel made of corundum, and then transferred to a high-temperature tube furnace. The temperature is then increased from room temperature to 700℃ at a rate of 2℃ / min, and calcined at this temperature for 16 hours. The high-temperature reaction of hydrogen and lithium sulfate is as follows:

[0080] 4H2(g)+Li2SO4(s)→Li2S(s)+4H2O(g);

[0081] S3. Collect the white powder under an inert atmosphere to obtain battery-grade lithium sulfide. Figure 4 These are the powder diffraction file and the XRD pattern of lithium sulfide.

[0082] Example 2

[0083] A method for preparing battery-grade lithium sulfide material includes the following steps:

[0084] S1. Weigh 2g of hydrated lithium sulfate and mechanically ball-mill it at 1700r / min for 2h to obtain fine powder of raw material;

[0085] S2. Under the protection of a hydrogen-argon mixture (5% H2), the fine powder of the raw material is filled into a cap-shaped reaction vessel made of corundum, and then transferred to a high-temperature tube furnace. The temperature is then increased from room temperature to 700℃ at a rate of 4℃ / min, and calcined at this temperature for 16 hours. The high-temperature reaction of hydrogen and lithium sulfate is as follows:

[0086] 4H2(g)+Li2SO4(s)→Li2S(s)+4H2O(g);

[0087] S3. Under an inert atmosphere, collect the white powder to obtain battery-grade lithium sulfide. Figure 5 These are the powder diffraction file and the XRD pattern of lithium sulfide.

[0088] Example 3

[0089] A method for preparing battery-grade lithium sulfide material includes the following steps:

[0090] S1. Weigh 1g (0.018mol) of anhydrous lithium sulfate and mechanically ball-mill it at 1700r / min for 4h to obtain fine powder of the raw material;

[0091] S2. Under the protection of a hydrogen-argon mixture (10% H2), the fine powder of the raw material is filled into a graphite crucible-shaped reaction vessel and then transferred to a high-temperature tube furnace. The temperature is then increased from room temperature to 800℃ at a rate of 5℃ / min and calcined at this temperature for 8 hours. The high-temperature reaction of hydrogen and lithium sulfate is as follows:

[0092] 4H2(g)+Li2SO4(s)→Li2S(s)+4H2O(g);

[0093] S3. Under an inert atmosphere, collect the white powder to obtain battery-grade lithium sulfide.

[0094] Figure 6 These are the powder diffraction file and the XRD pattern of lithium sulfide. Figure 7 The Raman spectra of lithium sulfide and its derivative prepared in Example 3 are shown. Figure 8 The image shows the SEM image of lithium sulfide prepared in Example 3. Figure 12 The graph shows the cycling performance of lithium sulfide prepared in Example 3 compared to existing lithium sulfide at 0.5C. Figure 13 The graph shows the cycle performance of a ternary lithium battery assembled with a solid electrolyte prepared from lithium sulfide in Example 3, compared to that prepared from existing lithium sulfide.

[0095] Example 4

[0096] A method for preparing battery-grade lithium sulfide material includes the following steps:

[0097] S1. Weigh 1g (0.018mol) of anhydrous lithium sulfate and 0.3g (4.02mmol) of nickel oxide, and mechanically ball-mill at 1700r / min for 6h to obtain fine powder of raw materials;

[0098] S2. Under the protection of a hydrogen-argon mixture (10% H2), the fine powder of the raw material is filled into a cap-shaped reaction vessel made of corundum, and then transferred to a high-temperature tube furnace. The temperature is then increased from room temperature to 900℃ at a rate of 5℃ / min, and calcined at this temperature for 8 hours. The high-temperature reaction of hydrogen, lithium sulfate, and nickel oxide is as follows:

[0099] 4H2(g)+Li2SO4(s)→Li2S(s)+4H2O(g)

[0100] H2(g) + NiO(s) → Ni(s) + H2O(g)

[0101] S3. Under an inert atmosphere, collect the black powder to obtain the lithium sulfide-catalyst composite material (Li2S-Ni).

[0102] Figure 9 These are the powder diffraction file and the XRD pattern of the lithium sulfide-catalyst composite material.

[0103] Example 5

[0104] A method for preparing battery-grade lithium sulfide material includes the following steps:

[0105] S1. Weigh 1g (0.018mol) of anhydrous lithium sulfate and 0.3g (1.067mmol) of cobalt sulfate heptahydrate, and mechanically ball-mill at 1700r / min for 5h to obtain fine powder of raw materials;

[0106] S2. Under the protection of a hydrogen-argon mixture (10% H2), the fine powder of the raw material is filled into a crucible-shaped reaction vessel made of corundum, and then transferred to a high-temperature tube furnace. The temperature is then increased from room temperature to 800℃ at a rate of 5℃ / min, and calcined at this temperature for 8 hours. The high-temperature reaction of hydrogen, lithium sulfate, and cobalt sulfate is as follows:

[0107] 4H2(g)+Li2SO4(s)→Li2S(s)+4H2O(g)

[0108] H2(g)+CoSO4(s)→Co9S8(s)+H2O(g)

[0109] S3. Under an inert atmosphere, collect the black powder to obtain the lithium sulfide-catalyst composite material (Li2S-Co9S8).

[0110] Figure 10 These are the powder diffraction file and the XRD pattern of the lithium sulfide-catalyst composite material. Figure 11 This is a graph showing the 0.5C cycle performance of the lithium sulfide-catalyst composite material prepared in Example 5 compared to that prepared in Example 3.

[0111] The battery-grade lithium sulfide materials prepared in all the above embodiments were characterized and subjected to electrochemical tests, and the results are as follows: Figures 4-13 As shown.

[0112] from Figures 4-7 As can be seen from the data, the lithium sulfide prepared by this invention corresponds one-to-one with the standard card, and there are no obvious impurity peaks.

[0113] from Figure 8 As can be seen from the above, the lithium sulfide prepared by this invention consists of blocky particles ranging from a few micrometers to tens of micrometers in size.

[0114] from Figure 9 As can be seen from the above, the present invention has successfully prepared lithium sulfide-nickel composite material.

[0115] from Figure 10 As can be seen from the above, the present invention successfully synthesized a lithium sulfide-cobalt sulfide composite material.

[0116] from Figure 11 As can be seen, the lithium sulfide-Co9S8 composite material prepared by this invention exhibits better battery cycle performance than lithium sulfide in lithium-sulfur battery tests, demonstrating the catalytic effect of Co9S8 and proving that this composite material has application prospects in lithium-sulfur batteries.

[0117] from Figure 12As can be seen from the results, the lithium sulfide prepared by this invention has comparable performance to commercial lithium sulfide in lithium-sulfur battery tests, proving that the preparation method of this invention has application prospects in lithium-sulfur batteries.

[0118] from Figure 13 As can be seen, the lithium sulfide prepared by this invention, as a raw material, synthesizes a solid electrolyte lithium phosphorus sulfide chlorine (LPSC), which exhibits comparable cycle performance to commercially prepared lithium sulfide in all-solid-state battery tests, proving that the preparation method of this invention has application prospects in solid-state batteries.

[0119] As described in the specification, those skilled in the art can modify the above embodiments. This invention is not limited to the above embodiments; any modifications, improvements, substitutions, or variations made within the concept and principles of this invention are within its protection scope. Specific terminology used in this specification is for ease of explanation and does not limit the scope of the invention.

Claims

1. A method for producing a battery-grade lithium sulfide material, characterized by, The application relates to a lithium sulfide preparation method. The raw material fine powder is obtained by mechanically ball-milling a sulfur source lithium source integrated compound or a mixture of the sulfur source lithium source integrated compound and a catalyst; The raw material fine powder is filled into a reaction container, and the raw material fine powder is calcined at high temperature under a pure hydrogen atmosphere or a hydrogen atmosphere with an inert gas as a carrier gas to obtain a solid product; The solid product is collected under the protection of an inert atmosphere, and a lithium sulfide or a lithium sulfide-catalyst composite material is obtained; The reaction container is a cap-sleeve type reaction container, and the material is one of graphite, metal, metal alloy, metal oxide; The cap-sleeve type reaction container comprises a cap-sleeve bottom, a cap-sleeve top and a ventilation pipe; the cap-sleeve bottom and the cap-sleeve top are internally provided with cavities, and are both open at one end and semi-closed at the other end due to the communication with the ventilation pipe; the cap-sleeve top is arranged inside the cap-sleeve bottom and is in a wedge key connection with the cap-sleeve bottom, wherein the open end of the cap-sleeve top is opposite to the semi-closed end of the cap-sleeve bottom; the ventilation pipe is provided with a neck-in near the positions of the cap-sleeve bottom and the cap-sleeve top, and quartz wool is arranged in the pipe section between the neck-in and the cap-sleeve bottom and the cap-sleeve top; The cap-sleeve type reaction container is arranged in a quartz tube, the two ends of the quartz tube are respectively connected with the ventilation pipes through flanges, the two ventilation pipes are respectively connected with the gas inlet pipe and the gas outlet pipe through connecting hoses, and the open end of the cap-sleeve top is open and faces the direction of the gas inlet pipe.

2. The method for preparing a battery-grade lithium sulfide material according to claim 1, characterized in that, The sulfur source lithium source integrated compound is lithium sulfate.

3. The method for preparing a battery-grade lithium sulfide material according to claim 1, characterized in that, The catalyst is a water-containing or water-free metal sulfate or a water-containing or water-free metal oxide.

4. The method for preparing a battery-grade lithium sulfide material according to claim 3, characterized in that, The water-containing or water-free metal sulfate is one of cobalt sulfate, nickel sulfate and zinc sulfate; the water-containing or water-free metal oxide is one of tricobalt tetraoxide, nickel protoxide and copper oxide.

5. The method for preparing a battery-grade lithium sulfide material according to claim 1, characterized in that, The hydrogen atmosphere with the inert gas as the carrier gas is one of hydrogen-argon mixed gas, hydrogen-nitrogen mixed gas and hydrogen-helium mixed gas.

6. The method for preparing a battery-grade lithium sulfide material according to claim 1, characterized in that, The material of the reaction container is graphite or corundum alumina.

7. The method for preparing a battery-grade lithium sulfide material according to claim 1, characterized in that, The temperature of the high-temperature calcination is 700-900 DEG C, and the time is 8-20 h.

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