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CN-121672427-B - Preparation method of lithium sulfide, product and application

CN121672427BCN 121672427 BCN121672427 BCN 121672427BCN-121672427-B

Abstract

The invention provides a preparation method of lithium sulfide, a product and application thereof, and belongs to the technical field of inorganic compound synthesis. According to the invention, anhydrous lithium hydroxide or lithium oxide is used as a lithium source, sulfur dioxide is used as an acidulant, hydrogen or methane is used as a reducing gas, and four steps of pretreatment of the lithium source, synthesis of a lithium sulfite intermediate, reduction of the lithium sulfite and post-treatment of a product are sequentially carried out, so that the lithium sulfide with high product purity and low carbon content is obtained, and the lithium sulfide can be directly applied to high-end fields such as all-solid batteries and lithium-sulfur batteries, and has important significance and wide industrialization application prospect in breaking through the industrialization bottleneck of all-solid batteries.

Inventors

  • XI JINXU
  • XU CHAO
  • ZHAN QIAN
  • YANG YANG
  • ZHU LINGYUN
  • SUN ZHENJIE

Assignees

  • 安徽金禾合成材料研究院有限公司
  • 安徽金禾实业股份有限公司

Dates

Publication Date
20260508
Application Date
20260210

Claims (18)

  1. 1. The preparation method of the lithium sulfide is characterized by comprising the following steps of: (1) The method comprises the steps of pretreatment of a lithium source, namely carrying out vacuum drying and water removal treatment on the lithium source to obtain the pretreated lithium source, wherein the lithium source is anhydrous lithium hydroxide or lithium oxide; (2) The preparation of the lithium sulfite intermediate, namely, sending the pretreated lithium source into a reactor, and introducing sulfur dioxide gas with the purity of more than or equal to 99.5% for reaction to produce the lithium sulfite intermediate; the reactor is a rotary kiln or a fluidized bed; When the reactor is a rotary kiln, the rotating speed is controlled to be 1-10r/min, the filling rate is controlled to be 10-30%, the reaction temperature of the low-temperature section is 50-80 ℃, the reaction condition is that the gas space velocity is 500-1000h -1 , the reaction time is 6-8h, the reaction temperature of the medium-temperature section is 100-320 ℃, the reaction condition is that the gas space velocity is 1000-2000h -1 , and the reaction time is 3-6h; When the reactor is a fluidized bed, controlling the apparent gas velocity of the gas to be 0.1-0.5m/s, the uniformity of the bed temperature to be +/-5 ℃, the reaction temperature of a low-temperature section to be 50-80 ℃ and the reaction time to be 4-6h, and the reaction temperature of a medium-temperature section to be 200-440 ℃ and the reaction time to be 2-4h; (3) The preparation of lithium sulfide, namely, introducing reducing gas into a reactor, and reacting with a lithium sulfite intermediate to obtain a lithium sulfide crude product; the reducing gas is hydrogen; Adopting a rotary kiln to connect reduction sections in series, taking hydrogen as reducing gas, firstly introducing inert gas with the purity of more than or equal to 99.99% into the reduction sections for purging and replacement, wherein the replacement time is 30-60min, ensuring the oxygen content to be less than 100ppm, then introducing hydrogen, controlling the rotary kiln rotation speed to be 1-8r/min and the filling rate to be 10-25%, and controlling the hydrogen reduction condition to be that the temperature is 300-450 ℃, the gas airspeed is 800-1500h -1 and the reaction time is 4-7h; Adopting fluidized bed integrated synthesis-reduction, taking hydrogen as reducing gas, firstly replacing a bed layer by inert gas for 20-40min, then switching into hydrogen, controlling the apparent gas velocity to be 0.1-0.6m/s, reducing the temperature to be 300-450 ℃ and the reaction time to be 3-6h; (4) And (3) after the reaction is finished, cooling the crude lithium sulfide product to room temperature, carrying out jet milling treatment, and directly carrying out vacuum drying after milling to obtain a lithium sulfide finished product.
  2. 2. The method of claim 1, wherein the purity of the lithium source in the step (1) is not less than 98%.
  3. 3. The preparation method according to claim 1, wherein the pretreatment in the step (1) is performed by: when the lithium source is anhydrous lithium hydroxide, the drying temperature is 200-430 ℃, the vacuum degree is-0.05 to-0.08 MPa, and the drying time is 2-3 hours; when the lithium source is lithium oxide, the drying temperature is 120-160 ℃, the vacuum degree is-0.05 to-0.08 MPa, and the drying time is 2-4h.
  4. 4. The method according to claim 3, wherein the pretreatment in the step (1) is performed by: When the lithium source is anhydrous lithium hydroxide, the drying temperature is 350 ℃, the vacuum degree is-0.06 MPa, and the drying time is 2.5 hours; when the lithium source is lithium oxide, the drying temperature is 150 ℃, the vacuum degree is-0.06 MPa, and the drying time is 3.5h.
  5. 5. The preparation method of the catalyst according to claim 1, wherein when the reactor is a rotary kiln, the rotation speed is controlled to be 5r/min, the filling rate is controlled to be 20%, the reaction temperature in the low-temperature section is 65 ℃, the reaction condition is that the gas space velocity is 800h -1 , the reaction time is 7h, the reaction temperature in the medium-temperature section is 250 ℃, the reaction condition is that the gas space velocity is 1800h -1 , and the reaction time is 5h.
  6. 6. The preparation method of the catalyst according to claim 1, wherein when the reactor is a fluidized bed, the apparent gas velocity of the gas is controlled to be 0.35m/s, the uniformity of the bed temperature is +/-5 ℃, the reaction temperature in the low-temperature section is 70 ℃, the reaction time is 5 hours, the reaction temperature in the medium-temperature section is 300 ℃, and the reaction time is 3 hours.
  7. 7. The process according to claim 1, wherein the molar ratio of the lithium source to sulfur dioxide in step (2) is 1:1.0-1.2.
  8. 8. The method of claim 7, wherein the molar ratio of the lithium source to sulfur dioxide in step (2) is 1:1.1.
  9. 9. The preparation method of the catalyst is characterized by adopting a rotary kiln to connect reduction sections in series and taking hydrogen as reducing gas, and specifically comprises the steps of firstly introducing inert gas with purity of more than or equal to 99.99% into the reduction sections for purging and replacement for 45min, ensuring oxygen content to be less than 100ppm, then introducing hydrogen, and controlling the rotating speed of the rotary kiln to be 5r/min and the filling rate to be 15%, wherein the hydrogen reduction condition is that the temperature is 400 ℃, the gas space velocity is 1200h -1 and the reaction time is 6h.
  10. 10. The method according to claim 1, wherein the reducing gas in the step (3) is methane.
  11. 11. The preparation method of the catalyst according to claim 10, wherein the rotary kiln is used for serial connection of reduction sections, methane is used as reducing gas, inert gas with purity of more than or equal to 99.99% is firstly introduced into the reduction sections for purging and replacement, replacement time is 30-60min, oxygen content is ensured to be less than 100ppm, and then methane is introduced for reduction under the conditions that reaction temperature is 450-600 ℃, gas airspeed is 600-1200h -1 and reaction time is 7-10h.
  12. 12. The preparation method of the catalyst according to claim 1, wherein the rotary kiln is adopted to connect the reduction sections in series, methane is used as a reducing gas, inert gas with the purity of more than or equal to 99.99% is firstly introduced into the reduction sections for purging and replacement for 50min, the oxygen content is ensured to be less than 100ppm, and then methane is introduced into the reduction sections for reduction under the conditions that the reaction temperature is 550 ℃, the gas space velocity is 1000h -1 and the reaction time is 9h.
  13. 13. The preparation method of the catalyst according to claim 1, wherein the fluidized bed integrated synthesis-reduction is adopted, hydrogen is used as a reducing gas, the bed is replaced by inert gas for 30min, then the reaction time is switched to hydrogen, the apparent gas velocity is controlled to be 0.4m/s, the reducing temperature is 400 ℃, and the reaction time is 4.5h.
  14. 14. The method of claim 1, wherein the fluidized bed integrated synthesis-reduction is adopted, methane is used as a reducing gas, the bed is replaced by inert gas for 30min, and then the reaction temperature is 550 ℃ and the reaction time is 7.5h.
  15. 15. The method of claim 1, wherein the jet milling process in the step (4) has the parameters of 0.7-1.0MPa of air inlet pressure, 10-30kg/h of feeding rate, 20000-30000r/min of classifying wheel speed, and the grain diameter D50 of the obtained lithium sulfide product is controlled within 3 μm.
  16. 16. The method of claim 1, wherein the vacuum drying in the step (4) is performed at a drying temperature of 80-120 ℃, a vacuum degree of-0.08 to-0.1 MPa and a drying time of 3-6 hours.
  17. 17. The lithium sulfide prepared by the preparation method according to any one of claims 1 to 16, wherein the purity of the lithium sulfide is not less than 99.9%, the carbon content is not more than 0.1%, and the particle diameter D50 is not more than 3. Mu.m.
  18. 18. Use of lithium sulfide prepared by the preparation method of any one of claims 1 to 16 for preparing a lithium-sulfur battery or a semiconductor electronic material.

Description

Preparation method of lithium sulfide, product and application Technical Field The invention belongs to the technical field of inorganic compound synthesis, and particularly relates to a preparation method, a product and application of lithium sulfide. Background Li 2 S is a typical inorganic compound, which belongs to the binary lithium salts and has a face-centered cubic crystal structure. Li 2 S is white or light yellow crystal at normal temperature and normal pressure, has a melting point of about 938 ℃ and a density of about 1.67g/cm 3, and has higher thermal stability and chemical stability. The lithium hydroxide and hydrogen sulfide gas are stable in inert atmosphere, are not easy to react with oxygen at room temperature, have reducibility at high temperature, can react with water to generate lithium hydroxide and hydrogen sulfide gas, and have strong hydrolyzability. Therefore, the preparation, storage and application processes must be tightly controlled with respect to ambient humidity and oxygen content. Li 2 S is a functional material with high theoretical specific capacity, high energy density and interface stability, and has wide application prospect in a plurality of high-performance fields, and is particularly important in an electrochemical energy storage system. In a new generation battery system such as a lithium sulfur battery and an all-solid-state battery, li 2 S can be used as a precursor of a positive electrode material or can participate in constructing a composite solid-state electrolyte under certain conditions. The charge excitation process of Li 2 S typically involves electrochemical reactions of the lithium ion battery, during which lithium ions migrate from the negative electrode to the positive electrode, and during excitation, electron transfer and chemical reactions also affect the lithiation process. The high-energy-density sulfide electrolyte has the advantages that the conductivity is obviously improved under the high-temperature condition, good interface matching can be formed with various sulfide electrolytes, and the high-energy-density sulfide electrolyte is an important basic material for realizing high energy density, safety and service life. In addition to battery systems, li 2 S plays a special role in the fields of thermoelectric materials, organic synthesis and functional ceramics. In the thermoelectric conversion direction, li 2 S is introduced into solid solutions such as Li-Sn-S, so that the carrier mobility and the thermoelectric figure of merit (ZT) can be effectively improved, and the method is suitable for high-temperature thermoelectric devices. In the fields of fine chemical engineering and drug synthesis, li 2 S is used as a sulfur source with high reactivity, can be used for constructing various sulfur-containing organic molecules such as thioether, sulfamide and ligand functional materials, and has unique advantages in high-selectivity synthesis and directional catalytic reaction. In battery technology, li 2 S applications have focused on lithium sulfur batteries and all-solid-state battery systems. Unlike a lithium metal anode, li 2 S has higher chemical stability and lower reactivity, is favorable for improving the safety of battery assembly, and avoids the safety risks of easy dendrite formation, short circuit induction and the like of lithium metal. In a lithium sulfur battery, li 2 S can be used as a pre-lithiated positive electrode precursor, the theoretical specific capacity of the lithium sulfur battery is far higher than that of a traditional oxide or phosphate positive electrode material, and the overall energy density can be greatly improved. In an all-solid-state system, the interface matching property of Li 2 S and a typical sulfide electrolyte is good, and the method is suitable for constructing a continuous ion channel structure and is beneficial to improving the charge transfer efficiency and the interface stability. The composite battery structure is particularly suitable for application scenes such as aerospace, military equipment, high-end electric automobiles and the like with extremely high requirements on energy density, safety and stability. However, in high performance battery applications, stringent requirements are placed on the purity and structure of the Li 2 S material. The presence of trace impurities, such as Li 2CO3、LiOH、Li2SO4, can interfere with electrode interface stability and increase side reaction propensity, thereby affecting cell cycle life and coulombic efficiency. Therefore, the reaction conditions are required to be strictly controlled in the material synthesis process, the purity of the product is ensured, and the uniform particle size distribution, pure crystal form and no impurity phase are realized. The high-purity Li 2 S material also has good micro-nano structure regulation and control capability, so that an electrode interface with large contact area is formed with electrolyte, and the reactio