Method for processing silica powder suitable for electrode material of lithium ion battery

Abstract

The invention relates to a method for processing silica powder suitable for an electrode material of a lithium ion battery. The method particularly comprises the following steps of: preparing a microemulsion system; sanding a microemulsion liquid phase; filtering and washing materials; atomizing and drying the washed materials for forming; and carrying out high-temperature heat treatment. According to the method, the microemulsion liquid phase is adopted as a grinding medium, and the high-purity silica powder is dispersed in microemulsion liquid drops in the sanding process, so that oxidization and monomer agglomeration can be avoided; spherical solid-phase silica powder particles are obtained by the atomizing and drying process; and finally, a product is further purified through the high-temperature heat treatment in a mixed atmosphere to obtain the superfine silica powder with good dispersity. The superfine silica powder provided by the method is good in dispersity and is 50-500 nm, optimally 50-200 nm, in particle size.

Description

technical field [0001] The invention relates to a processing method of silicon micropowder suitable for lithium ion battery electrode materials. Background technique [0002] Lithium-ion batteries have outstanding advantages such as high voltage, small size, light weight, high specific energy, no memory effect, no pollution, small self-discharge, and long life. They are considered to be the battery system with the best comprehensive performance at present. At present, commercialized lithium-ion battery anode materials mostly use various lithium-intercalated carbon materials, but the potential of the carbon electrode is very close to that of lithium. When the battery is overcharged, metal lithium may precipitate on the surface of the carbon electrode to form lithium dendrites. In addition, the theoretical capacity of carbon electrode materials is only 372mAh / g, which cannot meet the requirements of the miniaturization of various portable electronic devices and the requirement...

AI Technical Summary

Problems solved by technology

However, silicon material also has its shortcomings as the negative electrode material of lithium-ion batteries: 1. Huge volume effect, the volume change reaches more than 300% in the process of electrochemical lithium storage, which leads to the cracking and pulverization of silicon particles, and the loss of contact with the current collector. The electrical contact will eventually lead to a sharp attenuation of electrode capacity and a rapid decline in cycle performance; second, low conductivity, silicon itself is a semiconductor material, and the intrinsic conductivity is low, only 6.7×10 -4 S cm -1 , it is necessary to add a conductive agent to improve the electronic conductivity of the electrode; 3. Incompatibility with conventional electrolytes, silicon in conventional LiPF 6 It is difficult to form a stable surface solid electrolyte (SEI) film in the electrolyte, resulting in reduced charge and discharge efficiency and increased capacity fading

[0004] Silicon materials can achieve a high initial specific capacity (1000mAh / above) as the anode material of lithium-ion batteries, but the high irreversible capacity and poor cycle performance for the first time delay the process of realizing its commercial application

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