A prelithiation treatment method of a long-cycle silicon-oxygen negative electrode material

Abstract

The application relates to the technical field of lithium ion battery negative electrode material preparation, and specifically discloses a pre-lithiation treatment method of a long-cycle silicon-oxygen negative electrode material. The raw materials used in the method include silicon-oxygen negative electrode powder, lithium hydroxide monohydrate, lithium silicate seed crystals and anhydrous grinding aid. The raw materials are first classified and vacuum dried to control the initial water content. After the powder is uniformly mixed in an inert atmosphere, the grinding aid is added to prepare a paste-like mixture. The mixture is subjected to low-speed pre-reaction and high-speed deep-lithiation step-by-step ball milling treatment. The reaction endpoint is determined in two dimensions by combining the pressure threshold and the pressure increase rate. After ball milling, inert mixed gas containing carbon dioxide is introduced in situ to complete passivation. Finally, the pre-lithiated finished product is obtained through vacuum drying, post-treatment and screening. The method can direct the irreversible silicon dioxide phase pre-lithiation, reduce the damage of high-energy ball milling to the active silicon phase, has high pre-lithium depth control precision, omits the water washing post-treatment process, can simultaneously improve the first coulombic efficiency and long-cycle stability of the material, and is suitable for large-scale production requirements.