Preparation method of lithium sulfide, battery and lithium sulfide

Abstract

The invention relates to the technical field of lithium sulfide preparation, in particular to a lithium sulfide preparation method, a battery and lithium sulfide.The lithium sulfide preparation method comprises the steps that a lithium source, sulfur and a reducing substance are mixed to obtain a mixture raw material, the mixture raw material is heated to 200-1200 DEG C, and lithium sulfide is obtained. The preparation process provided by the invention is simple, and lithium sulfide can be obtained by mixing the lithium source, the sulfur and the reducing substance as raw materials and carrying out one-step reaction.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of lithium sulfide preparation, in particular to a lithium sulfide preparation method, a battery and lithium sulfide. BACKGROUND

[0002] As a key raw material for producing solid-state batteries and metal-sulfur battery systems, lithium sulfide makes metal lithium sulfide positive electrode materials widely used in safe and high-capacity lithium-sulfur batteries. The process for preparing lithium sulfide is relatively complex. SUMMARY

[0003] The main purpose of the application is to provide a lithium sulfide preparation method, which aims to improve the preparation process of lithium sulfide.

[0004] To achieve the above purpose, the application provides a lithium sulfide preparation method, which comprises the following steps:

[0005] Mixing a lithium source, sulfur and a reducing substance to obtain a mixture raw material;

[0006] Heating the mixture raw material to 200 DEG C to 1200 DEG C to obtain lithium sulfide.

[0007] The preparation method is simple. Specifically, a lithium source, sulfur and a reducing substance are mixed to obtain a mixture raw material, and the mixture raw material is heated to 200 DEG C to 1200 DEG C to obtain lithium sulfide.

[0008] Optionally, in the step of heating the mixture raw material to 200 DEG C to 1200 DEG C to obtain lithium sulfide, the step comprises:

[0009] Heating the mixture raw material to 200 DEG C to 250 DEG C, and then heating to 500 DEG C to 1200 DEG C to obtain lithium sulfide.

[0010] Considering that the product obtained in the process of heating the mixture raw material to 200 DEG C to 1200 DEG C to obtain lithium sulfide is a solid lithium sulfide block, the product is bonded to the reaction container and cannot be directly taken out, the product collection is time-consuming and laborious, and the yield cannot be calculated. Therefore, the mixture raw material is heated to 200 DEG C to 250 DEG C, and then heated to 500 DEG C to 1200 DEG C to obtain lithium sulfide, the obtained lithium sulfide product is in a powder state, so that the product is easy to collect, does not need to be ground, and due to the easy collection, the yield can be calculated, which is beneficial to large-scale industrial application.

[0011] It can be understood that during the reaction, the lithium source and the sulfur will react to produce lithium sulfide and various lithium polysulfides, the lithium polysulfides can further decompose into lithium sulfide and sulfur, the sulfur will be evaporated or react with water to generate hydrogen sulfide gas, and the final product is sulfur-free element, and the reducing agent can react with water and oxygen to protect the above reaction and protect the reaction of sulfur and lithium source to produce lithium sulfide and various lithium polysulfides, rather than lithium sulfate and lithium sulfite. Specifically, during the heating of the mixture raw material to 200-250°C, only water, lithium sulfide and various lithium polysulfides are actually generated, and the lithium polysulfides are decomposed into lithium sulfide and sulfur at a high temperature of 500-1200°C.

[0012] For example, in an embodiment, the reaction formula of the lithium source, the sulfur and the reducing agent under heating conditions is: 2LiOH+2S+2C==Li2S+H2S+2CO.

[0013] Optionally, in the step of heating the mixture raw material to 200-250°C and then heating to 500-1200°C to obtain lithium sulfide, the mixture raw material is heated to 205-250°C and then heated to 1010-1200°C to obtain lithium sulfide.

[0014] It can be understood that increasing the temperature can increase the reaction rate and make the reaction proceed effectively, and the above temperature range is set to improve production efficiency.

[0015] Optionally, in the step of heating the mixture raw material to 200-250°C and then heating to 500-1200°C to obtain lithium sulfide, the mixture raw material is heated to 205-250°C and then heated to 1010-1200°C to obtain lithium sulfide.

[0016] It can be understood that theoretically, the reaction of the lithium source and the sulfur to produce lithium sulfide and various lithium polysulfides starts at 200°C, and the reaction will accelerate as the temperature rises, and the lithium polysulfides are decomposed into lithium sulfide and sulfur at 500°C and above. High temperature can accelerate the reaction, but a large amount of reducing agent will be consumed at high temperature. In order to balance the reaction rate and the consumption of the reducing agent, the mixture raw material is heated to 205-250°C and then heated to 1010-1200°C to obtain lithium sulfide.

[0017] Optionally, the mass ratio of the lithium source to the sulfur is 10:(13.3-14.5).

[0018] In the case that the mixture raw material is heated to 200-250°C and then to 500-1200°C to obtain lithium sulfide, wherein the mass ratio of lithium source to sulfur meets the above range, the lithium source and sulfur can be fully reacted, i.e., the above reaction conditions are set according to the mechanism of lithium sulfide formation at high temperature, the raw material ratio is optimized, the reaction is effectively reacted below the melting point of lithium sulfide, and the product is in powder form. It can be understood that the product obtained by directly heating the sintering process (for example, heating to 300-1000°C) for high-temperature liquid-phase reaction and cooling is a solid lithium sulfide block, the product is bonded to the reaction container and cannot be directly taken out, the product collection is time-consuming and laborious, and the yield is difficult to calculate. In addition, if the reaction is not accurately controlled, the input sulfur powder cannot be effectively reacted, resulting in blockage of the reaction pipeline. These phenomena will make it difficult to be large-scale industrialized application. By using the above scheme, the product obtained is lithium sulfide powder, which makes the product easy to collect and does not need to be ground. Because of easy collection, the yield can be calculated, and because the amount of sulfur powder is optimized, the sulfur powder can be fully reacted, the problem of sulfur powder blocking the pipeline during the reaction process is solved, the yield is improved, the synthesis and process cost are greatly reduced, and large-scale industrialized application is possible.

[0019] Optionally, the mass ratio of the lithium source to the reducing agent is 1:(0.5-2).

[0020] In the case that the mass ratio of the lithium source to the reducing agent meets the above condition, the lithium source can be effectively reacted and the yield is improved.

[0021] Optionally, the lithium source includes at least one of lithium hydroxide and lithium carbonate.

[0022] In this application, the lithium source includes at least one of lithium hydroxide and lithium carbonate.

[0023] Optionally, the reducing agent includes at least one of a solid reducing agent, a gaseous reducing agent and a liquid reducing agent.

[0024] The solid reducing agent includes at least one of charcoal, coke, activated carbon, carbon black, bone charcoal and sugar charcoal.

[0025] The gaseous reducing agent includes at least one of hydrogen and carbon monoxide.

[0026] The liquid reducing agent includes glucose.

[0027] In this application, the reducing agent includes at least one of a solid reducing agent, a gaseous reducing agent and a liquid reducing agent.

[0028] The solid-state reducing material includes at least one of charcoal, coke, activated carbon, carbon black, bone charcoal, sugar charcoal; the gaseous reducing material includes at least one of hydrogen and carbon monoxide; and the liquid reducing material includes glucose, and it can be understood that the glucose is in liquid state at high temperature.

[0029] Optionally, the mass ratio of the lithium source, the sulfur and the solid-state reducing material is 10:(13.3-14.5):(2.5-5).

[0030] The mass ratio of the lithium source, the sulfur and the liquid reducing material is 10:(13.3-14.5):(2.5-5).

[0031] The flow rate of the gaseous reducing material is 0.05m 3 / min to 2m 3 / min.

[0032] The reducing material is used to protect the reaction of the sulfur and the lithium source to generate lithium sulfide and various lithium polysulfides, and not to generate lithium sulfate and lithium sulfite, the reducing material can react with water and oxygen, and the reducing material meeting the above range can effectively protect the above reaction.

[0033] It can be understood that if the amount of the solid-state reducing material is large, the un-consumed solid-state reducing material will exist in the product as impurities, and therefore, the mass ratio of the lithium source, the sulfur and the solid-state reducing material is set to 10:(13.3-14.5):(2.5-5), so as to reduce the impurities in the product.

[0034] Optionally, the preparation method of the lithium sulfide meets at least one of the following conditions:

[0035] The water content of the mixture raw material is less than or equal to 1000ppm.

[0036] There is no air in the container for the reaction of the mixture raw material.

[0037] The lithium polysulfide generated by the reaction of the sulfur and the lithium source has strong hygroscopicity, is easy to absorb water in the air to become liquid, and is partially oxidized to lithium sulfite, in order to reduce the above process, the water content of the mixture raw material is controlled to be less than or equal to 1000ppm, and there is no air in the container for the reaction of the mixture raw material. In addition, the lithium sulfide will deteriorate after absorbing water, and part of it will generate lithium hydroxide and hydrogen sulfide. The lithium hydroxide with high water content will become liquid in the reaction process, which will cause the whole material to solidify and not to obtain powder, and the subsequent process is difficult to handle.

[0038] It can be understood that, since the reducing agent reacts with the oxidizing agent, such as oxygen, in order to reduce the consumption of the reducing agent and effectively control the mass ratio of each raw material, before the reaction, the air in the reaction container for the raw material mixture can be first removed, and the reaction container is sealed during the reaction to prevent air from entering the reaction container. At the same time, the reaction container has an exhaust passage for discharging the gas generated during the reaction. For example, a tube furnace or a sealed furnace can be used as the reaction container, and after sealing, the gas outlet is oil sealed to prevent air from entering the reaction container.

[0039] Optionally, in the step of heating the mixture raw material to 200-1200℃ to obtain lithium sulfide, the step comprises: heating the mixture raw material in a reaction container to 200-1200℃ to obtain lithium sulfide, closing the gas outlet of the reaction container, and taking out the lithium sulfide after cooling.

[0040] It can also be understood that, after the reaction is completed, the gas outlet of the reaction container is closed, and the reaction product is taken out after the reaction container is cooled to room temperature. Considering that the gas outlet of the reaction container is sealed before the reaction, a negative pressure will be formed inside the reaction container after cooling, which can easily suck the liquid sealant of the sealed gas outlet, and at the same time, the reaction container can be naturally cooled during the cooling process, reducing the risk of damaging the reaction furnace due to too fast cooling during the cooling process.

[0041] Optionally, the application also provides a battery comprising a solid-state electrolyte, wherein the solid-state electrolyte comprises lithium sulfide prepared by the method for preparing lithium sulfide.

[0042] Alternatively, the battery comprises a positive electrode material, and the preparation raw material of the positive electrode material comprises lithium sulfide prepared by the method for preparing lithium sulfide.

[0043] The solid-state electrolyte is a solid ionic conductor electrolyte. Lithium sulfide can be applied in the solid-state electrolyte. Lithium sulfide can also be used as a raw material of a battery positive electrode material.

[0044] Optionally, the application also provides a lithium sulfide prepared by the method for preparing lithium sulfide.

[0045] The application mixes a lithium source, sulfur and a reducing agent to obtain a mixture raw material, and heats the mixture raw material to 200-1200℃ to obtain lithium sulfide. The preparation process of the application is simple. BRIEF DESCRIPTION OF DRAWINGS

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0047] FIG. 1 This is a schematic diagram of the process for preparing lithium sulfide.

[0048] FIG. 2 This is a schematic diagram of a battery cell according to one embodiment of this application;

[0049] FIG. 3 yes FIG. 2 An exploded view of a battery cell according to one embodiment of this application is shown.

[0050] FIG. 4 This is a schematic diagram of a battery module according to one embodiment of this application;

[0051] FIG. 5 This is a schematic diagram of a battery pack according to one embodiment of this application;

[0052] FIG. 6 yes FIG. 5 An exploded view of a battery pack according to one embodiment of this application is shown;

[0053] FIG. 7 This is a schematic diagram of an electrical device in which a single battery cell is used as a power source according to one embodiment of this application.

[0054] Explanation of icon numbers:

[0055] Reference Name Reference Name 1 Battery pack 5 Battery cell 2 Upper case 51 Housing 3 Lower case 52 Electrode assembly 4 Battery module 53 Cover plate

[0056] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0058] Hereinafter, the preparation method of lithium sulfide, the battery and the lithium sulfide according to the present application will be described in detail with appropriate reference to the accompanying drawings. However, there will be cases where unnecessary detailed descriptions are omitted. For example, there will be cases where detailed descriptions of matters known well, repetitive descriptions of substantially identical structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to sufficiently understand the present application, and are not intended to limit the subject matter recited in the claims.

[0059] The ranges disclosed herein are defined by their lower and upper limits. Ranges created by the upper and lower limits are inclusive of the endpoints. Ranges created by the upper and lower limits are also inclusive of any point or sub-range falling within the range. For example, if a range is stated as 60-120 and 80-110, it is understood that the range 60-110 and 80-120 are also contemplated. Furthermore, if a minimum range value of 1 and 2 is stated, and if a maximum range value of 3, 4, and 5 is stated, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise indicated, a numerical range "a-b" means a range of any combination of the numbers between the two endpoints a and b, wherein both a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein, and "0-5" is merely a shorthand for these numerical combinations. Also, when a parameter is stated to be an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0060] If not particularly stated, all the embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0061] If not particularly stated, all the technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0062] If not particularly stated, all the steps of the present application can be performed in sequence or randomly, and preferably in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order. For example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0063] As a key raw material for producing solid-state batteries and metal-sulfur battery systems, lithium sulfide makes sulfide positive electrode materials of metal lithium widely used in safe and high-capacity lithium-sulfur batteries. However, existing lithium sulfide generally has the disadvantage of high price, and the methods for preparing lithium sulfide in the laboratory can be roughly divided into ball milling, carbothermal reduction, mutual reaction of lithium / sulfur-containing compounds, and double decomposition.

[0064] The present application provides a simple preparation method of lithium sulfide, as shown in FIG. 1 The preparation method of lithium sulfide includes: mixing a lithium source, sulfur, and a reducing substance to obtain a mixture raw material; and heating the mixture raw material to 200-1200°C to obtain lithium sulfide.

[0065] The preparation method of the present application is simple, specifically, a lithium source, sulfur, and a reducing substance are mixed to obtain a mixture raw material, and the mixture raw material is heated to 200-1200°C to obtain lithium sulfide.

[0066] Considering that the product obtained by the above one-step heating method in the process of preparing lithium sulfide is a solid block, the solid block product is easy to stick to the reaction container and is difficult to directly take out, and the product is difficult to collect.

[0067] For example, in the process of preparing lithium sulfide, a sintering program is used to directly heat to 300-1000°C for high-temperature liquid phase reaction, and the product obtained after cooling is a solid lithium sulfide block, which is difficult to directly take out due to sticking to the reaction container, and the product is time-consuming and laborious to collect, and it is difficult to calculate the yield.

[0068] To solve the above problems, further, in the step of heating the mixture raw material to 200-1200°C to obtain lithium sulfide, it includes: heating the mixture raw material to 200-250°C, and then heating to 500-1200°C to obtain lithium sulfide.

[0069] Specifically, a lithium source, sulfur, and a reducing substance are mixed to obtain a mixture raw material, the mixture raw material is heated to 200-250°C, and then heated to 500-1200°C to obtain lithium sulfide. The preparation process of the present application is simple, the obtained lithium sulfide product is in a powder state, making the product easy to collect without the need for grinding, and due to easy collection, the yield can be calculated, which is beneficial to large-scale industrial application.

[0070] It can be understood that, in the reaction process, the lithium source and sulfur will react to produce lithium sulfide and various lithium polysulfides, the lithium polysulfides can further decompose into lithium sulfide and sulfur, the sulfur will be evaporated or react with water to generate hydrogen sulfide gas, and the final product is sulfur-free elemental sulfur, and the reducing agent can react with water and oxygen to protect the above reaction and protect the reaction of sulfur and lithium source to produce lithium sulfide and various lithium polysulfides, rather than lithium sulfate and lithium sulfite. Specifically, during the heating of the mixture raw material to 200-250°C, only water, lithium sulfide and various lithium polysulfides are actually generated, and the lithium polysulfides are decomposed into lithium sulfide and sulfur at a high temperature of 500-1200°C.

[0071] For example, in an embodiment, the reaction formula of the lithium source, sulfur and reducing agent under heating conditions is: 2LiOH+2S+2C==Li2S+H2S+2CO.

[0072] The above 200-250°C includes the minimum and maximum values of the range, and every value between such minimum and maximum values, and specific examples include but are not limited to point values in the embodiments and 200°C, 201°C, 202°C, 203°C, 204°C, 205°C, 207°C, 210°C, 212°C, 215°C, 217°C, 220°C, 221°C, 222°C, 223°C, 224°C, 225°C, 227°C, 230°C, 232°C, 235°C, 237°C, 240°C, 242°C, 245°C, 247°C, 248°C, 250°C, etc., and a range value between any two of the above point values.

[0073] The above 500-1200°C includes the minimum and maximum values of the range, and every value between such minimum and maximum values, and specific examples include but are not limited to point values in the embodiments and 500°C, 510°C, 550°C, 600°C, 610°C, 650°C, 680°C, 700°C, 710°C, 750°C, 780°C, 800°C, 810°C, 850°C, 880°C, 900°C, 910°C, 950°C, 980°C, 1000°C, 1010°C, 1050°C, 1080°C, 1200°C, etc., and a range value between any two of the above point values.

[0074] In an embodiment, in the step of heating the mixture raw material to 200-250°C and then heating to 500-1200°C to obtain lithium sulfide, the mixture raw material is heated to 205-250°C and then heated to 1010-1200°C to obtain lithium sulfide.

[0075] It can be understood that increasing the temperature can increase the reaction rate and make the reaction proceed effectively, and setting the above temperature range can improve production efficiency.

[0076] In an embodiment, in the step of heating the mixture raw material to 200-250 °C, and then heating to 500-1200 °C to obtain lithium sulfide, it comprises: heating the mixture raw material to 205-250 °C, maintaining for 4-10 h, and then heating to 1010-1200 °C, maintaining for 3-6 h to obtain lithium sulfide.

[0077] It can be understood that, in theory, lithium source and sulfur react to produce lithium sulfide and various polysulfides, which start to react at 200 °C, and the reaction will accelerate as the temperature rises. Polysulfides decompose into lithium sulfide and sulfur at 500 °C and above. Higher temperature can accelerate the reaction, but higher temperature will consume more reducing substances. In order to balance the reaction rate and the consumption of reducing substances, the mixture raw material is heated to 205-250 °C, maintained for 4-10 h, and then heated to 1010-1200 °C, maintained for 3-6 h to obtain lithium sulfide.

[0078] In the above 205-250 °C, the values include the minimum and maximum values of the range, and every value between such minimum and maximum values. Specific examples include but are not limited to point values in the embodiments and 205 °C, 207 °C, 210 °C, 212 °C, 215 °C, 217 °C, 220 °C, 221 °C, 222 °C, 223 °C, 224 °C, 225 °C, 227 °C, 230 °C, 232 °C, 235 °C, 237 °C, 240 °C, 242 °C, 245 °C, 247 °C, 248 °C, 250 °C, etc., and range values between any two of the above point values.

[0079] In the above 1010-1200 °C, the values include the minimum and maximum values of the range, and every value between such minimum and maximum values. Specific examples include but are not limited to point values in the embodiments and 1010 °C, 1020 °C, 1030 °C, 1040 °C, 1050 °C, 1060 °C, 1060 °C, 1080 °C, 1090 °C, 1110 °C, 1120 °C, 1130 °C, 1140 °C, 1150 °C, 1160 °C, 1160 °C, 1180 °C, 1190 °C, 1200 °C, etc., and range values between any two of the above point values.

[0080] In the above 4-10 h, the values include the minimum and maximum values of the range, and every value between such minimum and maximum values. Specific examples include but are not limited to point values in the embodiments and 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, etc., and range values between any two of the above point values.

[0081] The values ​​in the range 3h to 6h include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments, as well as 3h, 4h, 5h, 6h, etc., and the range values ​​between any two of the above point values.

[0082] In one embodiment, the mass ratio of lithium source to sulfur is 10:(13.3 to 14.5).

[0083] Because the product clumps during the one-step heating reaction, it is difficult to calculate the yield. As a result, the reaction cannot be precisely controlled, and the added sulfur powder may not react completely, which can lead to blockage of the reaction pipeline. This application designs experimental conditions based on the mechanism of lithium sulfide formation at high temperature and optimizes the raw material ratio so that the product is in powder form.

[0084] Lithium sulfide is obtained by heating the mixed raw materials to 200°C to 250°C, and then to 500°C to 1200°C. Under the condition that the mass ratio of lithium source to sulfur meets the above range, the lithium source and sulfur can react fully. That is, by setting the above reaction conditions according to the mechanism of lithium sulfide formation at high temperatures and optimizing the raw material ratio, the reaction can be carried out effectively below the melting point of lithium sulfide, resulting in a powdery product. It is understandable that directly heating the lithium sulfide sintering process (e.g., to 300°C to 1000°C) for a high-temperature liquid-phase reaction, the product obtained after cooling is a solid lithium sulfide block. The product adheres to the reaction vessel and cannot be directly removed, making product collection time-consuming, labor-intensive, and difficult to calculate the yield. Furthermore, if the reaction is not precisely controlled, the added sulfur powder cannot react effectively, leading to blockage of the reaction pipeline. These phenomena make it difficult to achieve large-scale industrial application. Using the above scheme, the product obtained is lithium sulfide powder, which makes the product easy to collect without grinding. Because it is easy to collect, the yield can be calculated. By optimizing the amount of sulfur powder, the sulfur powder can react fully, solving the problem of sulfur powder clogging the pipeline during the reaction process. At the same time, the yield is improved, the synthesis and process costs are greatly reduced, and it can be applied on a large scale in industry.

[0085] In the above 10: (13.3 to 14.5), the values ​​include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments and 10:13.3, 10:13.5, 10:13.7, 10:14.0, 10:14.1, 10:14.2, 10:14.3, 10:14.4, 10:14.5, etc., as well as the range values ​​between any two of the above point values.

[0086] In one embodiment, the mass ratio of lithium source to reducing agent is 1:(0.5 to 2).

[0087] The lithium source can be effectively reacted and the yield can be improved when the mass ratio of the lithium source and the reducing agent meets the above conditions.

[0088] In the above 1: (0.5 to 2), the values include the minimum and maximum values of the range, and every value between the minimum and maximum values, and specific examples include but are not limited to the point values in the embodiments and 1:0.5, 1:0.7, 1:0.9, 1:1, 1:1.1, 1:1.5, 1:1.7, 1:2, etc., and the range values between any two point values.

[0089] In an embodiment, the lithium source includes at least one of lithium hydroxide and lithium carbonate.

[0090] The lithium source in the present application includes at least one of lithium hydroxide and lithium carbonate.

[0091] Optionally, the reducing agent includes at least one of a solid reducing agent, a gaseous reducing agent, and a liquid reducing agent; the solid reducing agent includes at least one of charcoal, coke, activated carbon, carbon black, bone charcoal, and sugar charcoal; the gaseous reducing agent includes at least one of hydrogen and carbon monoxide; and the liquid reducing agent includes glucose.

[0092] The reducing agent in the present application includes at least one of a solid reducing agent, a gaseous reducing agent, and a liquid reducing agent. The solid reducing agent includes at least one of charcoal, coke, activated carbon, carbon black, bone charcoal, and sugar charcoal; the gaseous reducing agent includes at least one of hydrogen and carbon monoxide; and the liquid reducing agent includes glucose, which can be understood as being in a liquid state at high temperature.

[0093] In an embodiment, the mass ratio of the lithium source, sulfur, and the solid reducing agent is 10:(13.3 to 14.5):(2.5 to 5); the mass ratio of the lithium source, sulfur, and the liquid reducing agent is 10:(13.3 to 14.5):(2.5 to 5); and the flow rate of the gaseous reducing agent is 0.05 m 3 / min to 2 m 3 / min.

[0094] The reducing agent is used to protect the reaction of sulfur and the lithium source to generate lithium sulfide and various lithium polysulfides, without generating lithium sulfate and lithium sulfite. The reducing agent can react with water and oxygen. The reducing agent meeting the above range can effectively protect the above reaction. It can be understood that when the gaseous reducing agent is introduced during the reaction, the gaseous reducing agent can include other inert gases, such as argon, i.e., the gaseous reducing agent includes hydrogen-argon mixed gas.

[0095] It can be understood that if the amount of solid-state reducing material is large, the un-consumed solid-state reducing material will become an impurity in the product. Therefore, the mass ratio of the lithium source, sulfur, and solid-state reducing material is set to 10:(13.3 to 14.5):(2.5 to 5), which can reduce the impurities in the product.

[0096] In the above 10:(13.3 to 14.5):(2.5 to 5), the values include the minimum and maximum values of the range, and every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values in the examples and 10:13.3:2.5, 10:13.5:3, 10:13.7:4, 10:14.0:5, 10:14.1:2.5, 10:14.2:2.5, 10:14.3:3, 10:14.4:4, 10:14.5:5, and the range value between any two point values.

[0097] In the above 0.05m 3 / min to 2m 3 / min, the values include the minimum and maximum values of the range, and every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values in the examples and 0.05m 3 / min, 0.06m 3 / min, 0.07m 3 / min, 0.08m 3 / min, 0.09m 3 / min, 0.1m 3 / min, 0.2m 3 / min, 0.4m 3 / min, 0.6m 3 / min, 0.8m 3 / min, 1m 3 / min, 1.2m 3 / min, 1.4m 3 / min, 1.6m 3 / min, 1.8m 3 / min, 2m 3 / min, and the range value between any two point values.

[0098] In an embodiment, the method for preparing lithium sulfide satisfies at least one of the following conditions: the water content of the mixture raw material is 1000 ppm or less; and there is no air in the container for the reaction of the mixture raw material.

[0099] The lithium polysulfide generated by the reaction of sulfur and lithium source is highly hygroscopic, and is easily watered in the air to become liquid and partially oxidized to lithium sulfite. In order to reduce the occurrence of the above process, the water content of the mixture raw material is controlled to be less than or equal to 1000 ppm, and the container for the reaction of the mixture raw material is free of air. In addition, the lithium polysulfide is deteriorated after being watered, and part of it is generated as lithium hydroxide and hydrogen sulfide. The lithium hydroxide with a higher water content is liquid in the reaction process, which leads to the solidification of the material and the difficulty in subsequent processing.

[0100] It can be understood that, since the reducing agent reacts with the oxidizing agent, such as oxygen, in order to reduce the consumption of the reducing agent and effectively control the mass ratio of each raw material, the air in the reaction container for the reaction of the mixture raw material can be removed before the reaction, and the reaction container is sealed during the reaction to avoid the air entering the reaction container. In addition, the reaction container has an exhaust passage for discharging the gas generated in the reaction process. For example, a tube furnace or a sealed furnace can be used as the reaction container, and the gas outlet is sealed with oil after sealing to avoid the air entering the reaction container.

[0101] In an embodiment, in the step of heating the mixture raw material to 200-1200°C to obtain lithium polysulfide, the step includes: heating the mixture raw material in the reaction container to 200-1200°C to obtain lithium polysulfide, closing the gas outlet of the reaction container, and taking out the lithium polysulfide after cooling.

[0102] It can also be understood that, after the reaction is completed, the gas outlet of the reaction container is closed, and the reaction product is taken out after the reaction container is cooled to room temperature. Considering that the gas outlet of the reaction container is sealed before the reaction, a negative pressure is formed in the reaction container after cooling, which easily sucks the liquid sealant of the sealed gas outlet, and the reaction container can be naturally cooled during the cooling process, which reduces the risk of damaging the reaction furnace due to too fast cooling during the cooling process.

[0103] In an embodiment, the application also provides a lithium polysulfide, which is prepared by the preparation method of the lithium polysulfide.

[0104] In an embodiment, the application also provides the application of the lithium polysulfide or the lithium polysulfide prepared by the preparation method of the lithium polysulfide.

[0105] In an embodiment, the application also provides a battery, which includes a solid-state electrolyte containing the lithium polysulfide prepared by the preparation method of the lithium polysulfide, or a positive electrode material containing the lithium polysulfide prepared by the preparation method of the lithium polysulfide. The solid-state electrolyte is a solid ionic conductor electrolyte. The lithium polysulfide can be applied in the solid-state electrolyte. The lithium polysulfide can also be used as a raw material of the positive electrode material of the battery. In addition, the lithium polysulfide can also be used as an additive of glass, ceramic and the like.

[0106] In an embodiment, the application also provides a power consuming device, which comprises the battery as described above.

[0107] It can be understood that the battery comprises a battery cell, a battery module, and a battery pack.

[0108] In addition, the battery (battery cell, battery module, and battery pack) and the power consuming device of the application are described below with appropriate reference to the accompanying drawings.

[0109] In an embodiment of the application, a battery cell is provided.

[0110] Generally, the battery cell comprises a positive electrode sheet, a negative electrode sheet, an electrolyte, and a separator. During the charging and discharging of the battery, active ions are inserted into and extracted from the positive electrode sheet and the negative electrode sheet. The electrolyte serves to conduct ions between the positive electrode sheet and the negative electrode sheet. The separator is arranged between the positive electrode sheet and the negative electrode sheet and mainly serves to prevent the short circuit of the positive electrode and the negative electrode while allowing ions to pass through. The separator is the improved separator as described above.

[0111] The positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector.

[0112] For example, the positive electrode current collector has two opposite surfaces in the thickness direction thereof, and the positive electrode film layer is arranged on any one or both of the two opposite surfaces of the positive electrode current collector.

[0113] In some embodiments, the positive electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, an aluminum foil can be used. The composite current collector can comprise a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0114] In some embodiments, when the electrode assembly is a lithium ion battery, the positive electrode active material can employ a positive electrode active material for a lithium ion battery known in the art. As an example, the positive electrode active material can include at least one of a lithium-containing phosphate of an olivine structure, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a positive electrode active material for a battery can also be used. These positive electrode active materials can be used alone only or in combination of two or more. Among them, examples of the lithium transition metal oxide can include, but are not limited to, lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3Mn 1 / 3 O2(also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2(also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2(also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2(also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2(also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05 O2), and a modified compound thereof, etc. Examples of the lithium-containing phosphate of an olivine structure can include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4(also referred to as LFP)), a composite of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite of lithium manganese iron phosphate and carbon.

[0115] The battery is accompanied by Li deintercalation and consumption during charging and discharging, and the molar content of Li is different when the battery is discharged to different states. In the enumeration of the positive electrode material in the present application, the molar content of Li is the initial state of the material, i.e., the state before feeding, and the positive electrode material is applied to the battery system. After charging and discharging cycles, the molar content of Li will change.

[0116] In the list of the positive electrode material in the present application, the molar content of O is only the theoretical value, and the oxygen release of the crystal lattice will cause the change of the molar content of O, and the actual molar content of O will appear to be floating.

[0117] In some embodiments, the positive electrode film layer further optionally includes a binder. As an example, the binder can include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylic ester resin.

[0118] In some embodiments, the positive electrode film layer further optionally includes a conductive agent. As an example, the conductive agent can include at least one of super conductive carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0119] In some embodiments, the positive electrode tab can be prepared by dispersing the above-mentioned components for preparing the positive electrode tab, such as the positive electrode active material, the conductive agent, the binder, and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry on a positive electrode current collector, and after processes such as drying, cold pressing, etc., the positive electrode tab can be obtained.

[0120] The negative electrode tab includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.

[0121] As an example, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0122] In some embodiments, the negative electrode current collector can adopt a metal foil or a composite current collector. For example, as the metal foil, a copper foil can be adopted. The composite current collector can include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base material. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material base material (such as a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0123] In some embodiments, the negative active material can employ a negative active material for a battery known in the art. As an example, the negative active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, etc. The silicon-based material can be selected from at least one of elemental silicon, silicon oxide compound, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy. The tin-based material can be selected from at least one of elemental tin, tin oxide compound, and tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a negative active material for a battery can also be used. These negative active materials can be used alone or in combination of two or more.

[0124] In some embodiments, the negative film layer can further optionally include a binder. The binder can be selected from at least one of styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0125] In some embodiments, the negative film layer can further optionally include a conductive agent. The conductive agent can be selected from at least one of super conductive carbon, acetylene black, carbon black, ketjen black, carbon dot, carbon nanotube, graphene, and carbon nanofiber.

[0126] In some embodiments, the negative film layer can further optionally include other auxiliary agents, such as thickening agents (e.g., sodium carboxymethyl cellulose (CMC-Na)) and the like.

[0127] In some embodiments, the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as the negative active material, the conductive agent, the binder, and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry on a negative current collector, and after processes such as drying, cold pressing, etc., the negative electrode sheet can be obtained.

[0128] The electrolyte plays a role of conducting ions between the positive electrode sheet and the negative electrode sheet. The present application does not have a specific limitation on the type of electrolyte, which can be selected as needed.

[0129] In some embodiments, the electrolyte employs an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.

[0130] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclobutane sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0131] In some embodiments, the electrolyte can further include an additive capable of improving certain performance of the battery, such as an additive for improving overcharge performance of the battery, an additive for improving high-temperature or low-temperature performance of the battery, etc.

[0132] In some embodiments, a separator is further included in the battery cell. The type of the separator is not particularly limited in the present application, and any publicly known porous structure separator having good chemical stability and mechanical stability can be used.

[0133] In some embodiments, the material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single layer film or a multi-layer composite film, and is not particularly limited. When the separator is a multi-layer composite film, the materials of the respective layers can be the same or different, and are not particularly limited.

[0134] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator can be used to make an electrode assembly through a winding process or a stacking process.

[0135] In some embodiments, the battery cell can include an outer package. The outer package can be used to package the electrode assembly and the electrolyte described above.

[0136] In some embodiments, the outer package of the battery cell can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package of the battery cell can also be a soft package, such as a pouch-type soft package. The material of the soft package can be plastic, and as the plastic, polypropylene, polybutylene terephthalate, polybutylene succinate, etc. can be listed.

[0137] The shape of the battery cell is not particularly limited in the present application, and it can be cylindrical, square, or any other shape. For example, FIG. 2 is a square structure battery cell 5 as an example.

[0138] In some embodiments, with reference to FIG. 3The outer package can include a housing 51 and a cover plate 53. The housing 51 can include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be arranged on the opening to close the receiving cavity. The positive electrode tab, the negative electrode tab, and the separator can form the electrode assembly 52 through a winding process or a stacking process. The electrode assembly 52 is packaged in the receiving cavity. The electrolyte is impregnated in the electrode assembly 52. The number of electrode assemblies 52 contained in the battery cell 5 can be one or more, and the number can be selected by those skilled in the art according to the actual needs.

[0139] In some embodiments, the battery cell can be assembled into a battery module, and the number of battery cells contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0140] FIG. 4 The battery module 4 is an example. Referring to FIG. 4 In the battery module 4, a plurality of battery cells 5 can be arranged in sequence along the length direction of the battery module 4. Of course, other arbitrary arrangements can also be used. Further, the plurality of battery cells 5 can be fixed by fasteners.

[0141] Optionally, the battery module 4 can also include a housing having a receiving space, and the plurality of battery cells 5 are received in the receiving space.

[0142] In some embodiments, the above-mentioned battery module can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0143] FIG. 5 And FIG. 6 The battery pack 1 is an example. Referring to FIG. 5 And FIG. 6 The battery pack 1 can include a battery box and a plurality of battery modules 4 arranged in the battery box. The battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be arranged on the lower box body 3 to form a closed space for receiving the battery module 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0144] In addition, the application also provides a power utilization device, which comprises at least one of the battery monomer, the battery module or the battery pack provided by the application. The battery monomer, the battery module or the battery pack can be used as a power supply of the power utilization device, or can be used as an energy storage unit of the power utilization device. The power utilization device can include a mobile device (such as a mobile phone, a notebook computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc., but is not limited thereto.

[0145] As the power utilization device, the battery monomer, the battery module or the battery pack can be selected according to the use requirement thereof.

[0146] FIG. 7 The power utilization device is taken as an example. The power utilization device is a pure electric vehicle, a hybrid electric vehicle or a plug-in hybrid electric vehicle, etc. In order to meet the requirement of high power and high energy density of the battery monomer for the power utilization device, the battery pack or the battery module can be used.

[0147] The device taken as another example can be a mobile phone, a tablet computer, a notebook computer, etc. The device usually requires thinning, and the battery monomer can be used as a power supply.

[0148] Embodiment

[0149] Embodiment 1

[0150] Preparation of lithium sulfide

[0151] 10 g of lithium hydroxide, 13.3 g of sulfur powder and 2 g of activated carbon powder were mixed well, placed in a porcelain boat and covered with a lid. The porcelain boat was placed in a tube furnace, and the exhaust port was sealed with oil seal after sealing. The tube furnace was heated to 210℃ for 8h, and then heated to 1010℃ for 3h, and then cooled after closing the exhaust port of the tube furnace. After cooling, the powder product was weighed and calculated for yield and tested for lithium sulfide purity.

[0152] Embodiments 2 to 14

[0153] On the basis of embodiment 1, the mass ratio of lithium hydroxide, sulfur, reducing material and the temperature rising procedure were adjusted to obtain the data of embodiments 2 to 14 in tables 1 and 2 of the embodiment.

[0154] Embodiment 15: The raw materials lithium hydroxide, sulfur powder and activated carbon with a mass of 10 g, 13 g and 3 g were mixed well and placed in a reaction container, and then heated to 700℃ for high-temperature liquid-phase reaction for 4h. After cooling, the obtained product was a solid lithium sulfide block.

[0155] Performance test

[0156] The purity of lithium sulfide is tested by iodometric titration. 20 ml of iodine standard titration solution is pipetted into a 250 ml iodometric flask, 25 ml of water, 10 ml of glacial acetic acid are added, the experimental product is added under shaking, and the solution is titrated with sodium thiosulfate standard titration solution. When the solution is light yellow, 2 ml of starch indicator solution is added. Continue titration until the blue color disappears as the end point.

[0157] Result calculation:

[0158] V1 is the volume value of the iodine standard titration solution added, in ml;

[0159] V2 is the value of the sodium thiosulfate standard titration solution consumed in titration, in ml;

[0160] V3 is the value of the volume of iodine standard titration solution consumed in titration, in ml;

[0161] C1 is the accurate value of the concentration of the iodine standard titration solution, in mol / L;

[0162] C2 is the accurate value of the concentration of the sodium thiosulfate standard titration solution, in mol / L;

[0163] M is the value of the molar mass of sodium sulfide (1 / 2 Na2S), in g / mol;

[0164] m is the mass of the experimental product, in g;

[0165] The arithmetic mean of the parallel test results is the test result, and the absolute difference of the parallel test results is not greater than 0.3%.

[0166] The yield is calculated based on lithium hydroxide. Theoretically, the mass of lithium sulfide that can be generated is compared with the actual mass of lithium sulfide received.

[0167] Table 1 Example List

[0168]

[0169] Table 2 Example List

[0170]

[0171]

[0172] From the above table 1 and table 2, it can be understood that the higher the temperature, the higher the consumption of reducing substances such as carbon, and if the carbon is consumed, the lithium sulfide will be oxidized into lithium sulfate, and the product form can roughly judge what the by-product is. Lithium sulfide is theoretically white, and the product is black powder, indicating that the activated carbon is not completely consumed. The product is brown, or light brown, which can be inferred that the activated carbon is basically completely consumed, and the low purity may generate impurities lithium sulfate. The scheme of the present application can obtain lithium sulfide with high purity, and although the product contains impurities, the impurities are less, which can reduce the purification cost.

[0173] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or the like made under the inventive concept of the present application and using the content of the present application specification and drawings are included in the patent protection scope of the present application.

Claims

1. A method for producing lithium sulfide, characterized by, The method comprises the following steps: Mixing a lithium source, sulfur and a reducing substance to obtain a mixture raw material; Heating the mixture raw material to 200-1200℃ to obtain lithium sulfide.

2. The method for producing lithium sulfide according to claim 1, characterized by, In the step of heating the mixture raw material to 200-1200℃ to obtain lithium sulfide, the step comprises the following steps: Heating the mixture raw material to 200-250℃, and then heating to 500-1200℃ to obtain lithium sulfide.

3. The method for producing lithium sulfide according to claim 2, characterized by, In the step of heating the mixture raw material to 200-250℃, and then heating to 500-1200℃ to obtain lithium sulfide, the step comprises the following steps: heating the mixture raw material to 205-250℃, and then heating to 1010-1200℃ to obtain lithium sulfide.

4. The method for producing lithium sulfide according to claim 2 or 3, characterized by, In the step of heating the mixture raw material to 200-250℃, and then heating to 500-1200℃ to obtain lithium sulfide, the step comprises the following steps: heating the mixture raw material to 205-250℃ for 4-10 hours, and then heating to 1010-1200℃ for 3-6 hours to obtain lithium sulfide.

5. The method for producing lithium sulfide according to any one of claims 1 to 4, wherein At least one of the following conditions is met: The mass ratio of the lithium source to the sulfur is 10:(13.3-14.5); The mass ratio of the lithium source to the reducing substance is 1:(0.5-2); The lithium source comprises at least one of lithium hydroxide and lithium carbonate.

6. The method for producing lithium sulfide according to any one of claims 1 to 5, wherein The reducing substance comprises at least one of solid-state reducing substance, gaseous reducing substance and liquid reducing substance; The solid-state reducing substance comprises at least one of charcoal, coke, activated carbon, carbon black, bone charcoal and sugar charcoal; The gaseous reducing substance comprises at least one of hydrogen and carbon monoxide; The liquid reducing substance comprises glucose.

7. The method for producing lithium sulfide according to claim 6, wherein At least one of the following conditions is met: The mass ratio of the lithium source to the sulfur to the solid-state reducing substance is 10:(13.3-14.5):(2.5-5); The mass ratio of the lithium source to the sulfur to the liquid reducing substance is 10:(13.3-14.5):(2.5-5); The flow rate of the gaseous reducing substance is 0.05 m 3 / min to 2 m 3 / min.

8. The method for producing lithium sulfide according to any one of claims 1 to 7, wherein At least one of the following conditions is met: The water content of the mixture raw material is less than or equal to 1000 ppm; There is no air in the container for the reaction of the mixture raw material.

9. The method for producing lithium sulfide according to any one of claims 1 to 8, wherein In the step of heating the mixture raw material to 200-1200℃ to obtain lithium sulfide, the step comprises the following steps: Heating the mixture raw material in a reaction container to 200-1200℃ to obtain lithium sulfide; Closing the gas outlet of the reaction container, and taking out the lithium sulfide after cooling.

10. A battery, characterized by The battery comprises a solid-state electrolyte, and the solid-state electrolyte comprises lithium sulfide prepared by the method for preparing lithium sulfide according to any one of claims 1-9. Alternatively, the battery comprises a positive electrode material, and the preparation raw material of the positive electrode material comprises lithium sulfide prepared by the method for preparing lithium sulfide according to any one of claims 1-9.

11. Lithium sulfide characterized in that, The lithium sulfide comprises lithium sulfide prepared by the method for preparing lithium sulfide according to any one of claims 1-9.

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