736 results about "Lithium sulfide" patented technology

Disclosed in the present invention are a bimetallic-atom-loaded porous carbon framework material, and a preparation method therefor and the use thereof. The preparation method comprises: by taking a metal organic framework as a precursor raw material, and by using the self-polymerization of a high-molecular polymer on the surface of the metal organic framework, forming a polymer-coated metal-based organic framework material (PM@MOF) having a core-shell structure; and then capturing the metal of a metal chloride salt solution by using surface functional groups of the PM@MOF dispersed in n-hexane, so as to obtain a bimetallic element-doped polymer-coated metal-based organic framework material, and subjecting same to a high-temperature treatment in an argon gas atmosphere so as to obtain a bimetallic-atom-loaded porous carbon-based material (MD@PC). In the present invention, by loading bimetallic atoms on a nitrogen-doped porous carbon matrix to form MD-NX coordination sites, which have the dual functions of sulfur fixation and catalysis, the agglomeration degree of intermediate phase lithium sulfide can be reduced, thereby guaranteeing that the lithiation reaction of sulfur is more sufficient, rapid and efficient.

The invention relates to a method for preparing lithium sulfide, which comprises the following steps: respectively dissolving a sulfur source compound and a lithium source compound in alcohol under the protection of inert atmosphere, and then mixing the two alcohol solutions for double decomposition reaction to generate a lithium sulfide suspension; and then carrying out evaporative crystallization, supercritical fluid washing, centrifugal separation and freeze drying treatment to obtain a lithium sulfide product. The purity of the lithium sulfide prepared through the method can reach 99.9% or above, the lithium sulfide can be used as a positive electrode material of a lithium-sulfur battery or a raw material of a sulfide solid electrolyte in an all-solid-state battery, and the method is low in energy consumption, conforms to the concept of green chemistry and is suitable for large-scale industrial production.

The invention provides lithium sulfide as well as a preparation method and application thereof. The preparation method of the lithium sulfide comprises the following steps: providing a mixed solution containing a lithium-containing compound and liquid sulfur which are uniformly mixed, and enabling the mixed solution to be in contact with a reducing gas so as to carry out a lithium sulfide synthesis reaction, after the synthesis reaction of the lithium sulfide is finished, at least removing part of sulfur in the obtained reaction mixture to obtain a crude finished product; and calcining the crude finished product to convert lithium polysulfide in the crude finished product into lithium sulfide to obtain a lithium sulfide product. According to the preparation method provided by the invention, the high-purity lithium sulfide is prepared by a one-pot method, the liquid sulfur is used as a reaction raw material and a reaction solvent, and the whole reaction process does not need to use an organic solvent; according to the method, the lithium salt conversion rate can reach 99% or above, and the purity of the obtained lithium sulfide can reach 99.99% or above; compared with the prior art, the reaction temperature is lower, and low energy consumption and high conversion rate are both considered.

The invention relates to the technical field of battery production, and discloses a preparation method of high-purity lithium sulfide, which comprises the following steps: preparing high-purity sulfur powder; pretreating lithium hydride; proportioning and feeding; carrying out high-speed ball milling treatment; cooling at normal temperature; carrying out ball milling detection; and collecting and packaging. According to the preparation method of the high-purity lithium sulfide, the argon is filled in the ball milling tank, so that the reaction between the lithium hydride and the high-purity sulfur powder is always carried out under the protection of the argon, the safety of the reaction can be ensured, and meanwhile, the use of toxic gas in the production process of the lithium sulfide can be reduced; the high efficiency and safety of the lithium sulfide production process are guaranteed, meanwhile, the converter with the rotating structure at the bottom of the ball milling tank drives the ball milling tank to continuously rotate, full heating and heating uniformity of lithium hydride and high-purity sulfur powder are guaranteed, and then the reaction efficiency and safety of the device in the high-purity lithium sulfide preparation process are improved.

The invention provides a method for preparing high-purity and fine-particle-size lithium sulfide based on carbon thermal reduction. The method comprises the following steps: weighing lithium sulfate monohydrate, an insoluble inorganic carbon source and cysteine in a set proportion to form a raw material mixture; mixing the raw material mixture with water according to a set solid-to-liquid ratio, performing ultrasonic dispersion to obtain homogeneous dispersion liquid, and enabling the dispersion liquid to pass through a nitrogen circulating spray dryer to obtain uniform and dry precursor powder; in a vacuum environment, carrying out segmented calcination to obtain a crude product lithium sulfide; and in a dry and anhydrous environment, washing the crude product lithium sulfide for multiple times by using absolute ethyl alcohol according to a set liquid-solid ratio to obtain an alcoholic solution containing lithium sulfide, and then obtaining lithium sulfide fine powder through a nitrogen circulating spray dryer. The invention solves the problems of side reaction, low purity, large product particles, uncontrollable particle size and the like of lithium sulfide prepared by a carbon thermal reduction method in the prior art.

The embodiment of the invention provides a synthesis method and application of lithium sulfide. The synthesis method of the lithium sulfide comprises the following steps: providing a sulfur source and a lithium source; performing first treatment on the sulfur source to obtain sulfur vapor; performing second treatment on the lithium source to obtain molten metal lithium; and in an inert atmosphere, introducing the sulfur vapor into the molten metal lithium, and reacting to generate lithium sulfide. According to the synthesis method and application of the lithium sulfide provided by the embodiment of the invention, the sulfur source is converted into the sulfur vapor, the lithium source is converted into the molten metal lithium, and the gas-liquid out-phase reaction is carried out in the inert atmosphere, so that the reaction efficiency and the purity are improved, the process is simplified, the cost is reduced, and the high-purity requirement can be met; the purity can be improved through raw material pretreatment of sulfur steam and molten metal lithium, and the strict requirement of a solid-state battery for high-purity lithium sulfide is met.

The invention discloses high-purity lithium sulfide as well as a preparation method and application thereof. The preparation method comprises the step that lithium hydride, lithium hydroxide and a sulfur source are subjected to a heating reaction in a dry inert atmosphere, and the high-purity lithium sulfide is obtained. The molar ratio of lithium hydride to lithium hydroxide is X: (10-X), and X is 1-6. The invention also discloses the prepared high-purity lithium sulfide and application of the high-purity lithium sulfide in preparation of sulfide solid electrolyte. Lithium hydroxide and lithium hydride are mixed to serve as a lithium source in lithium sulfide preparation, the lithium hydroxide quickly and uniformly reaches the reaction temperature by means of the characteristic that the lithium hydride reacts with a sulfur source to release heat and produce gas, the lithium hydride reacts to produce gas, meanwhile, discharging of product water vapor is facilitated, and oxygen in the environment is isolated; and hardening and generation of a side reaction product lithium sulfate are prevented, the conversion rate of lithium hydroxide to lithium sulfide is improved, and the raw material and process cost for preparing lithium sulfide is remarkably reduced.

Preparation of anhydrous lithium sulfide (Li2S) purified suitably for applications in advanced batteries, and, in particular, for synthesis of solid electrolytes based on Li2S, including sulfide solid electrolytes of the type that may be described as crystalline (e.g., polycrystalline), amorphous (e.g., glass) and combinations thereof, such as sulfide glass-ceramic solid electrolyte materials.

The invention provides a modified lithium sulfide solid electrolyte, a sulfide solid electrolyte, a preparation method thereof and a battery, and relates to the technical field of solid electrolyte materials. The preparation method of the sulfide solid electrolyte is different from a traditional doping technology, the high-stability sulfide solid electrolyte is prepared mainly through modification of lithium sulfide, the comprehensive performance of the sulfide solid electrolyte is improved, the ionic conductivity and chemical stability of the sulfide solid electrolyte are improved, and the service life of the sulfide solid electrolyte is prolonged. And the mechanical strength and the crack resistance are also obviously enhanced. The preparation method disclosed by the invention is simple, does not need to be carried out at high temperature, and does not need to use expensive raw materials and complex processes, so that the production cost is reduced, the application range of the sulfide solid electrolyte is expanded, and large-scale production and application of the sulfide solid electrolyte are favorably realized.

The invention relates to the technical field of solid-state electrolytes, and discloses a high-ionic-conductivity solid-state electrolyte, a preparation method thereof and a solid-state battery. The preparation method comprises the following steps: mixing lithium sulfide, lithium chloride, lithium oxide, phosphorus pentasulfide and boron nitride in an inert atmosphere to obtain a mixture; carrying out ball milling on the mixture to obtain precursor powder; and sintering the precursor powder, and dispersing the sintered precursor powder to obtain the high-ionic-conductivity solid electrolyte. The boron element, the nitrogen element and the oxygen element are introduced into a lithium phosphorus sulfur chlorine system as doping elements, lattice parameters of LPSC are changed through the boron element, the rotation rate of a PS4 / BS4 tetrahedron is enhanced, and a lithium ion diffusion channel is optimized, so that the lithium ion transition activation energy of the electrolyte is reduced, the migration rate of lithium ions is increased, and the performance of the electrolyte is improved. Therefore, the solid electrolyte has high ionic conductivity. The introduced nitrogen element and oxygen element can interact with atoms such as sulfur and phosphorus, the electron cloud distribution of anion groups is adjusted, the interaction energy of lithium ions and the anion groups is reduced, the lithium ion transmission performance is further improved, and the electrochemical stability of the anion framework is enhanced. This makes it possible to increase the energy density of an all-solid-state battery when used in a solid-state battery.

A lithium ion-conductive solid electrolyte including a freestanding inorganic vitreous sheet of sulfide-based lithium ion conducting glass is capable of high performance in a lithium metal battery by providing a high degree of lithium ion conductivity while being highly resistant to the initiation and / or propagation of lithium dendrites. Such an electrolyte is also itself manufacturable, and readily adaptable for battery cell and cell component manufacture, in a cost-effective, scalable manner. An automated machine based system, apparatus and methods assessing and inspecting the quality of such vitreous solid electrolyte sheets, electrode sub-assemblies and lithium electrode assemblies can be based on spectrophotometry and can be performed inline with fabricating the sheet or web (e.g., inline with drawing of the vitreous Li ion conducting glass) and / or with the manufacturing of associated electrode sub-assemblies and lithium electrode assemblies and battery cells.

The invention provides a synthesis method of nanoscale lithium sulfide, and relates to the technical field of lithium sulfide synthesis. The synthesis method provided by the invention comprises the following steps: stirring and dissolving a lithium sulfide raw material in an alcohol solvent, and separating to obtain a lithium sulfide alcohol solution; evaporating, crystallizing and drying the lithium sulfide alcohol solution to obtain lithium sulfide crystals; and mixing the lithium sulfide crystals with a sulfur source, and firing at 550-850 DEG C to obtain the nanoscale lithium sulfide. The nanoscale lithium sulfide is directly synthesized in one step through a solid-phase sintering method, the operation method is simple, the cost is low, and large-scale industrial production can be achieved.

The invention belongs to the technical field of lithium battery materials, and particularly relates to a preparation method of high-purity lithium sulfide. Comprising the following steps: putting lithium hydroxide and pure water into a reaction kettle, replacing air in the reaction kettle with nitrogen, starting the reaction kettle, and stirring and heating; introducing quantitative hydrogen sulfide gas from the bottom of the reaction kettle, and circulating the gas in the reaction kettle between liquid in the reaction kettle and a gas space through a gas circulating pump; and after the temperature of the reaction liquid in the kettle is reduced to 20-30 DEG C, filtering in a nitrogen atmosphere, washing the residual solid with quantitative ammonia water, transferring the filtered solid into a drying box, and purging and drying with nitrogen until no water exists, thereby obtaining the high-purity lithium sulfide. In the solvent method, water is used for replacing an organic solvent for reaction, the problems of organic solvent separation and recovery, hazardous waste treatment and the like are avoided, the cost is reduced, and the method is environment-friendly.

The invention provides a preparation method of high-purity and low-cost lithium sulfide and lithium sulfide prepared by the preparation method, and relates to the field of lithium sulfide materials. According to the preparation method of the high-purity and low-cost lithium sulfide, on the basis of the characteristics of high-efficiency heat and mass transfer and uniform dispersion of a fluidized bed fluidization technology, lithium source small liquid drops are coated on the surface of a fluidized precursor, then hydrogen sulfide gas is introduced, the lithium source melt liquid drops or the precursor coated with the lithium source solution liquid drops are subjected to a contact reaction with the hydrogen sulfide gas, and the high-purity and low-cost lithium sulfide is obtained. The lithium sulfide is prepared. According to the preparation method of the high-purity and low-cost lithium sulfide, the problems of more reaction byproducts, low hydrogen sulfide gas utilization rate, easiness in product agglomeration and non-uniform particle size distribution in the existing lithium sulfide preparation process can be effectively solved, the reaction temperature is further reduced, and the production safety is improved; and the problem that the product purity and quality are influenced by water vapor in the preparation process is effectively avoided, and stable and efficient lithium sulfide production is realized.

The present invention relates to a carbon structure, which can stably support a high content of sulfur in pores and has excellent electrical conductivity properties, wherein the carbon structure is a polyhedron, of which the center on at least one side is concave, and is a highly graphitized nitrogen-doped porous carbon structure. Therefore, the stability of lithium-sulfur batteries can be improved by effectively suppressing a s shuttle phenomenon occurring during an electrochemical reaction of lithium-sulfur batteries containing, as a cathode active material, the carbon structure supporting sulfur as well as minimizing the volume change resulting from sulfur and reduced lithium sulfide.

The invention discloses a large-scale preparation method of lithium sulfide, and belongs to the technical field of preparation of battery materials. Lithium sulfate monohydrate is adopted as a reaction raw material and is subjected to dehydration and purification treatment to obtain anhydrous lithium sulfate, and the anhydrous lithium sulfate is calcined in hydrogen and carbon dioxide mixed gas without introducing other impurities; the method has the advantages that safety under high-temperature calcination reaction can be guaranteed, the produced lithium sulfide crude product is dissolved by the methanol / isopropanol mixed solution to directly generate lithium sulfide crystals, redundant impurities can be removed by calcining the generated lithium sulfide crystals, no other by-products are generated in the reaction process, and the purity of lithium sulfide is guaranteed. According to the Li2S preparation method developed by increasing the purification step and exploring the reaction conditions and the impurity removal mode, low-cost, high-purity and large-scale preparation of Li2S can be realized.

The invention provides a modified lithium metal negative electrode and a preparation method and application thereof, and belongs to the technical field of lithium batteries. The modified lithium metal negative electrode comprises a negative electrode conductive substrate and an interface passivation layer formed on the surface of the negative electrode conductive substrate, and the interface passivation layer comprises lithium oxide, lithium sulfide, lithium nitride, lithium fluoride and a fluorocarbon compound; the interface passivation layer is obtained by putting lithium metal into chloroform for dipping treatment to obtain modified lithium metal and then performing plasma treatment. According to the lithium ion battery, the interface passivation film containing the lithium oxide, the lithium sulfide, the lithium nitride, the lithium fluoride and the fluorocarbon is formed on the negative electrode conductive substrate, and in the repeated charging and discharging process of the lithium ion battery, due to the existence of the interface passivation film, non-uniform deposition of lithium ions can be avoided, so that growth of lithium dendrites is inhibited. Furthermore, the coulombic efficiency and the cycling stability of the charge-discharge cycle of the lithium ion battery can be improved, and the service life of the lithium ion battery is prolonged.

The present invention provides a method for preparing a carbon-containing lithium sulfide composite material, the method comprising: in a water-free and oxygen-free environment of a vacuum glove box, weighing a certain amount of lithium source and sulfur source, putting them into a ball mill, and then adding sodium borohydride according to a set ratio to mix evenly; sealing the ball mill, and passing an inert gas after evacuation, and then ball milling for a certain time at a set speed and after the ball milling is completed, taking out the lithium sulfide solid under the protection of the inert gas; dissolving and filtering the obtained lithium sulfide solid in anhydrous ethanol, and adding a certain amount of carbon source to the filtrate, stirring, and ultrasonic treatment; heating and evaporating to remove the solvent, and obtaining a solid Li2S / C precursor; placing the Li2S / C precursor in a vacuum freeze dryer, and freeze-drying to remove residual moisture to obtain a Li2S / C composite material. The present invention solves the problems of high cost and low purity when preparing lithium sulfide in the prior art.

The invention provides a preparation method and application of lithium sulfide. The preparation method comprises the following steps: reacting a lithium source with a sulfur source; the lithium source is a solid lithium-containing substance with the purity of 99% or above and the whiteness of 86 or above; the solid lithium-containing substance is selected from one or more of anhydrous lithium hydroxide, lithium hydroxide monohydrate, lithium carbonate, lithium chloride, lithium bromide and lithium nitrate. According to the method, a solid lithium-containing substance with the purity of 99% or above and the whiteness of 86 or above is used as a lithium source and reacts with a sulfur source, and the ionic conductivity value of the Li6PS5Cl solid electrolyte prepared from the obtained lithium sulfide is stable. Experimental results show that the ionic conductivity can stably reach more than 2mS / cm.

The invention belongs to the technical field of solid-state batteries, and provides a lithium-sulfur-phosphorus-chlorine-bromine solid-state electrolyte, a preparation method thereof and an all-solid-state battery. The preparation method comprises the following steps: mixing lithium sulfide and phosphorus sulfide, and carrying out ball milling to obtain a lithium-sulfur-phosphorus ternary mixture; in protective gas, the lithium-sulfur-phosphorus ternary mixture, lithium chloride and lithium bromide are mixed and then subjected to ball milling, and a lithium-sulfur-phosphorus-chlorine-bromine mixture is obtained; and carrying out heat treatment on the lithium-sulfur-phosphorus-chlorine-bromine mixture in protective gas to obtain the lithium-sulfur-phosphorus-chlorine-bromine solid electrolyte. The lithium-sulfur-phosphorus-chlorine-bromine solid electrolyte provided by the invention not only improves the electrochemical stability, but also maintains the high ionic conductivity characteristic.

The invention discloses a process for directly synthesizing battery-grade lithium sulfide, which comprises the following steps: enabling metal lithium and sulfur to directly react in an inert gas atmosphere under the conditions of 30-350kPa and 945-1320 DEG C to generate a reaction product A containing lithium sulfide and lithium polysulfide; the molar ratio of metal lithium to sulfur is 1: (15-32); reducing the temperature of the reaction product A to 390-705 DEG C, carrying out countercurrent contact reaction on the reaction product A and hydrogen at 20-65 DEG C, and converting lithium polysulfide into lithium sulfide to obtain a reaction product B; and cooling and crushing the reaction product B to obtain the battery-grade lithium sulfide. The method is low in raw material cost, high in product purity and capable of fully recovering heat energy.

The invention relates to a sulfide solid electrolyte and a preparation method and application thereof, and the preparation method comprises the following steps: distributing elemental sulfur powder on the surface of lithium sulfide powder to obtain composite powder; mixing the composite powder with phosphorus sulfide and lithium halide to obtain a precursor; and sintering the precursor to obtain the sulfide solid electrolyte. According to the preparation method disclosed by the invention, the elemental sulfur powder is distributed on the surface of the lithium sulfide powder, so that the elemental sulfur powder can participate in formation of the sulfide solid electrolyte before volatilization in the sintering process, the prepared sulfide solid electrolyte does not have sulfur loss, and no impurity phase is generated in the sulfide solid electrolyte; therefore, the ionic conductivity of the sulfide solid-state electrolyte can be improved, and the electrochemical performance of an all-solid-state battery can be obviously improved when the sulfide solid-state electrolyte is used for assembling the all-solid-state battery; meanwhile, the preparation method is simple and efficient, and the obtained sulfide solid electrolyte is uniform in performance.

The invention provides a method for preparing high-purity lithium sulfide from lithium carbonate, and belongs to the technical field of lithium material preparation, and the method comprises the following steps: heating a ball-milled mixture of industrial-grade lithium carbonate and an alumina additive to 750-900 DEG C, and carrying out heat preservation and calcination to generate lithium oxide; performing hydrolysis reaction on lithium oxide in hot water, and filtering to obtain a high-purity lithium hydroxide solution; mixing the lithium hydroxide solution with the sulfur-containing protein, and performing spray drying to obtain a mixed precursor; calcining the mixed precursor at a low temperature of 210-340 DEG C in an inert atmosphere; and heating to 550-660 DEG C, calcining at a high temperature, introducing hydrogen sulfide gas, reacting lithium hydroxide to generate lithium sulfide, and cooling to obtain the high-purity lithium sulfide. The invention provides the method for preparing the high-purity lithium sulfide, the purity, the production efficiency and the raw material utilization rate of the lithium sulfide are remarkably improved, and the technical defects of low purity, incomplete raw material reaction, non-uniform precursor mixing, complicated process, difficulty in large-scale production and the like in the traditional lithium sulfide preparation method are overcome.

The invention relates to the technical field of preparation of lithium sulfide, in particular to a method for preparing lithium sulfide through hydrogen reduction of lithium sulfate. According to the specific technical scheme, the method for preparing the lithium sulfide by reducing the lithium sulfate through the hydrogen comprises the steps that the lithium sulfate is smashed to be micron-sized and then fed into a fluidized bed reactor, then high-purity hydrogen preheated to 850 DEG C is introduced into the fluidized bed reactor from the bottom of the fluidized bed reactor, the reaction temperature is controlled to be 850 + / -20 DEG C, and the reaction time is controlled to be 5-10 min. The hydrogen reduction method is relatively low in reaction temperature (700-900 DEG C), hydrogen is used as a clean reducing agent, a reaction byproduct is only water, and the problems of insufficient purity, high energy consumption, serious environmental pollution and the like in a traditional lithium sulfide preparation method can be avoided. The introduction of the fluidized bed technology can greatly enhance the gas-solid phase heat and mass transfer efficiency, realizes the continuity and automation of the process, and is an important path for realizing the industrialization of the reaction.

The invention discloses a preparation method of a high-performance lithium-phosphorus-sulfur-chlorine solid electrolyte, and relates to the technical field of solid-state lithium batteries. The method comprises the following steps: in an inert atmosphere environment, selecting lithium sulfide, phosphorus pentasulfide, sulfur and lithium chloride as raw materials, carrying out mechanical alloying treatment through a high-energy ball milling method, then promoting crystallization through heat treatment, and finally optimizing the particle size distribution of the material through powder grading. The method provided by the invention can effectively improve the ionic conductivity of lithium phosphorus sulfur chlorine, and the solid electrolyte with good fluidity and stability is obtained.

The invention relates to the technical field of battery raw materials, in particular to a preparation method of lithium sulfide powder, the lithium sulfide powder and application, and the preparation method comprises the following steps: uniformly mixing lithium sulfate and a carbon source according to a preset proportion to obtain a first mixture; performing first heat treatment on the first mixture in inert gas to obtain a second mixture; and performing second heat treatment on the second mixture in reducing gas to obtain the lithium sulfide powder. The product obtained by the preparation method disclosed by the invention is the lithium sulfide powder, and the obtained lithium sulfide powder has the advantages of less oxygen and carbon impurities, higher purity and high reaction activity, and meets the synthesis requirements of the electrolyte; according to the preparation method, in the process of preparing lithium sulfide, toxic gas and organic solvent are not used, the reaction temperature is low, the energy consumption is low, the requirement on production equipment is low, the process is simple, the cost is low, harmful gas emission is avoided, safety and environment friendliness are achieved, and industrialization is easy to achieve.

The invention relates to the field of new energy batteries, in particular to a sulfide solid electrolyte, a preparation method thereof and a battery, the preparation method comprises the following steps: S1, dissolving lithium sulfide and lithium halide in an anhydrous organic solvent to obtain a first material; drying the first material to obtain a first mixture; s2, mixing the first mixture with phosphorus sulfide to obtain a precursor; and S3, carrying out sintering treatment on the precursor. The preparation method of the sulfide solid electrolyte is simple and efficient in process and low in preparation cost, uniform mixing of high-melting-point raw materials can be achieved, then uniform mixing of precursors is achieved, and the solid electrolyte prepared through the method is free of impurity phases and high in batch stability.

The invention belongs to the technical field of lithium-containing waste treatment, and particularly discloses a method for preparing lithium carbonate by recycling lithium through cooperative treatment of lithium-containing waste. The method specifically comprises the following steps: mixing a lithium amide waste material, a lithium sulfide waste material and water, then mixing with a hydrogen peroxide solution and a sulfuric acid solution, and carrying out an acid dissolution reaction to obtain a lithium-containing acid solution and an insoluble substance; mixing the lithium-containing acid solution with alkali liquor, and carrying out alkalization reaction to obtain insoluble impurities and alkalized feed liquid; concentrating the alkalized feed liquid to obtain concentrated alkalized feed liquid, and mixing the concentrated alkalized feed liquid with a sodium carbonate solution for lithium precipitation reaction to obtain lithium precipitation mother liquor and lithium carbonate; extracting the lithium element in the lithium precipitation mother liquor, and evaporating and concentrating the raffinate to separate out sodium sulfate and ammonium sulfate; ammonium sulfate and the lithium iron phosphate waste are mixed and then sequentially subjected to roasting and leaching, and a leaching solution and a lithium-containing acid solution are mixed for alkalization. The method has the characteristics of high process integration level, high economic value and less environmental pollution, and conforms to the new concept of chemical green atom economy.

The invention relates to the technical field of lithium sulfide preparation, and particularly discloses a preparation method of lithium sulfide. The preparation method of the lithium sulfide comprises the following steps: grinding and mixing lithium sulfate, chitin and derivatives thereof, then putting the mixed material into a corundum crucible, putting the corundum crucible into a tubular furnace, heating to 250 DEG C at a heating rate of 7 DEG C / min in a nitrogen atmosphere, keeping the temperature for 1 hour, and cooling to room temperature to obtain the lithium sulfide. Then heating to 300 DEG C at a heating rate of 1 DEG C / min in a nitrogen atmosphere, keeping the temperature for 5 hours, carrying out a carbonization coating reaction, then heating to 700 DEG C at a heating rate of 5 DEG C / min in a nitrogen atmosphere, keeping the temperature for 10 hours, carrying out an oxidation-reduction reaction, and finally grinding to obtain lithium sulfide. The preparation method of the lithium sulfide powder provided by the invention is simple in process flow, the requirement on environment control is reduced, and the preparation method is low in raw material price, relatively few in working procedures, low in preparation cost and suitable for large-scale industrial production.

The invention relates to a solid-phase preparation method and application of battery-grade lithium sulfide, and the preparation method comprises the following steps: (1) firstly, adopting industrial-grade lithium carbonate as a raw material, and carrying out pretreatment purification to remove sodium-calcium-magnesium metal ion impurities; (2) carrying out ball-milling mixing on the purified lithium carbonate raw material and sulfur powder, and carrying out low-temperature melting pre-sintering; (3) performing primary high-temperature calcination on the lithium carbonate and sulfur powder mixture under a protective atmosphere to synthesize a lithium sulfide crude product; (4) carrying out secondary high-temperature calcination on the lithium sulfide crude product in a protective atmosphere to remove excessive sulfur impurities and lithium polysulfide impurities so as to obtain purified lithium sulfide; and (5) carrying out ball milling and crushing on the obtained lithium sulfide, and screening to obtain the battery-grade lithium sulfide with different particle sizes. According to the preparation method, a high-temperature solid-phase synthesis method is adopted, and low-temperature melting pre-sintering and high-temperature two-step calcining methods are adopted, so that reaction byproducts are gas and are easy to remove, production and preparation of high-purity battery-grade lithium sulfide can be realized, and the product has excellent electrochemical performance.