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CN-121974299-A - Electrode material precursor lithium sulfide, preparation method thereof and lithium-sulfur battery positive electrode material

CN121974299ACN 121974299 ACN121974299 ACN 121974299ACN-121974299-A

Abstract

The invention belongs to the technical field of electrode materials, and in particular relates to an electrode material precursor lithium sulfide, a preparation method thereof and a lithium-sulfur battery positive electrode material, which comprises the following steps of mixing sulfur powder and lithium scraps in a glove box under an inert gas atmosphere to obtain a primary mixture; the method comprises the steps of loading a primary mixture and grinding balls into a ball milling tank, sealing, installing the ball milling tank on a planetary ball mill, enabling sulfur powder and lithium scraps to react through ball milling, placing the ball milling tank into ice water bath for cooling after ball milling is finished, controlling the reaction temperature through an intermittent operation mode, and carrying out annealing treatment on generated lithium sulfide fine powder to obtain a product lithium sulfide. The preparation method of the lithium sulfide solves the problems of low product purity, complicated post-treatment, high energy consumption and low atomic economy, and is beneficial to promoting the industrial application process of the lithium sulfide.

Inventors

  • LV JIA
  • ZHAO YIHAN
  • CUI HAO

Assignees

  • 杭州元威企业管理合伙企业(有限合伙)

Dates

Publication Date
20260505
Application Date
20260204

Claims (10)

  1. 1. The preparation method of the electrode material precursor lithium sulfide is characterized by comprising the following steps: In a glove box filled with inert gas, taking sulfur powder and lithium scraps as reaction materials, and putting the reaction materials and grinding balls into a ball milling tank and sealing, wherein the molar ratio of the sulfur powder to the lithium scraps is 2:1, and the total mass ratio of the grinding balls to the reaction materials is 15-30:1; Ball-milling the reaction materials in the ball-milling tank to react sulfur powder with lithium scraps, wherein the reaction temperature is controlled by adopting an intermittent operation mode in the ball-milling process; and carrying out annealing treatment on the generated lithium sulfide fine powder to obtain a product lithium sulfide.
  2. 2. The method according to claim 1, wherein the revolution speed is 300 to 450 rpm during ball milling, and the ball milling is suspended for 15 to 30 minutes each time for 30 to 50 minutes.
  3. 3. The method according to claim 1, wherein the surface temperature of the ball milling tank is monitored during the ball milling process to ensure that the temperature does not exceed 50 ℃, and the total effective ball milling time is controlled between 10 and 24 hours.
  4. 4. The preparation method according to claim 1, wherein the grinding balls are of different diameters, and the grinding balls are mixed, wherein phi 5mm and phi 10mm are half of each other.
  5. 5. The method according to claim 1, wherein the annealing is performed in a vacuum atmosphere or a protective atmosphere at 200 ℃ to 350 ℃ for 1 to 3 hours.
  6. 6. The preparation method according to claim 1, wherein the raw material consumption is calculated according to the molar ratio of the sulfur powder to the lithium dust being 2:1, and lithium is excessive by 1% -3% in actual weighing.
  7. 7. The preparation method according to claim 1, wherein the purity of the sulfur powder is not less than 99.5%, the particle size distribution D50 is not more than 15 μm, the purity of the lithium chips is not less than 99.9%, and the area of the lithium chips is 1-3 mm < 2 >.
  8. 8. The preparation method according to claim 1, wherein the sulfur powder and the lithium dust are premixed in a glove box to obtain a premix, and the premix and the grinding balls are placed in a ball mill pot and sealed.
  9. 9. The electrode material precursor lithium sulfide is characterized in that the electrode material precursor lithium sulfide is prepared by the preparation method of any one of claims 1-8, the particle size of the lithium sulfide is 30-60 nm, the specific surface area is 5m 2 /g~20m 2 /g, the cubic system is of an inverse fluorite structure, the purity is more than or equal to 99.9%, and the total content of metal impurities is less than 300 ppm.
  10. 10. A positive electrode material for a lithium-sulfur battery, characterized by being prepared from the electrode material precursor lithium sulfide of claim 9, a conductive agent and a binder.

Description

Electrode material precursor lithium sulfide, preparation method thereof and lithium-sulfur battery positive electrode material Technical Field The invention belongs to the technical field of electrode materials, and particularly relates to an electrode material precursor lithium sulfide, a preparation method thereof and a lithium-sulfur battery positive electrode material. Background With the development of new energy automobile industry, lithium sulfide is used as an important inorganic compound, and is not only a positive electrode material precursor of a high-performance lithium-sulfur battery, but also a key electrolyte or electrode material precursor in an all-solid-state battery. The parameters of purity, crystal structure, oxygen content, etc. directly affect the energy density, cycle life and safety of the final battery product. At present, the industrialized preparation method of lithium sulfide mainly comprises the following steps: (1) Carbothermal reduction method, li 2SO4 +C.fwdarw.Li (high temperature) 2S+CO2 And uniformly mixing anhydrous lithium sulfate with excessive carbon powder (such as glucose), and reacting at a high temperature of 900-1000 ℃ under the protection of inert gas. In this process, carbon acts as a reducing agent to reduce lithium sulfate, forming a lithium sulfide solid and releasing carbon dioxide gas. After the reaction is finished, a solid mixture of lithium sulfide and glucose is generated, the glucose is removed after dissolving and filtering by ethanol, and then the lithium sulfide ethanol solution is decompressed and sintered to obtain a lithium sulfide product extremely sensitive to water and oxygen. The defects are that carbon impurities possibly remain in the product, the purity of the obtained product is not high, higher purity cannot be achieved, a complex of lithium sulfide and ethanol is generated, and the ethanol is difficult to remove. (2) Lithium chloride and sodium sulfide 2LiCl+Na 2S→2Li2 S+NaCl By which the metathesis reaction takes place in a strictly deoxygenated, dehydrated solvent, such as absolute ethanol. And adding sodium sulfide solution into lithium chloride solution under the protection of inert atmosphere to generate lithium sulfide precipitate, and then filtering or centrifuging to separate the precipitate, filtering, washing, vacuum and sintering to obtain the final product extremely sensitive to water and air. The disadvantages are that the product separation and washing steps are cumbersome and impurities are easily introduced or the product is lost during the process. Methanol is difficult to remove and forms a complex with lithium sulfide easily. (3) Lithium hydroxide and hydrogen sulfide reaction process of 2LiOH+H 2S→Li2S+2H2 O Lithium hydroxide was dissolved in p-xylene to form a suspension. Hydrogen sulfide gas is slowly and stably introduced into the suspension under the protection of inert gas. In the reaction process, lithium hydroxide and hydrogen sulfide undergo solid-gas heterogeneous neutralization reaction in a paraxylene medium to gradually generate lithium sulfide solid. Because the paraxylene has the characteristic of azeotropy with water, the water generated by the reaction can be taken away, thereby greatly inhibiting the hydrolysis side reaction of lithium sulfide. After the reaction is completed, the product is separated by hot filtration around the boiling temperature of para-xylene and washed with hot anhydrous para-xylene to remove possible impurities. And finally, thoroughly drying the obtained solid under the high-temperature vacuum condition to obtain high-purity lithium sulfide powder. The disadvantage is that water is produced by the reaction, and hydrogen sulfide gas is produced by the reaction with water. The reaction needs hydrogen sulfide, the side reaction is easy to generate hydrogen sulfide gas, and the consumption is high for experimental safety and subsequent environment-friendly treatment. (4) The reaction method of simple substance lithium and simple substance sulfur is 2Li+S- & gtLi 2 S The sulfur powder was placed into the bottom of a stainless steel ampoule and then the lithium block was placed over the sulfur powder (both not mixed). The lid is covered (temporary unsealed). The ampoule is quickly removed and connected to a high vacuum system. After vacuum or a small charge of argon, the ampoule is completely sealed with oxyhydrogen flame or arc welding. And (5) placing the sealed ampoule into a program temperature control furnace, and placing an explosion-proof baffle in front of the ampoule. Then, a key temperature raising program is carried out, namely room temperature is changed to 120 ℃, and the temperature raising rate is 1 ℃ per minute (sulfur is melted and the reaction is started). 120 ℃ to 180 ℃ and the temperature rising rate is 0.5 ℃ per minute (core reaction zone, severe overheat prevention). Keeping the temperature at 180 ℃ for 10-24 hours. Program cooling after reaction or cooled to