Spherical graphite with median diameter of 17 to 30 mu m and preparation method thereof

Abstract

The invention discloses a preparation method of spherical graphite by natural crystalline flake graphite with a median diameter of 3 to 10 mu m. A five-level powder refining machine set consisting of an air-flow vortex powder refining machine and a cyclone separator is sequentially connected with a fourteen-level nodulizing machine set consisting of an air-flow vortex nodulizing machine and a nodulizing classifier in series; the graphite material enters from the first powder refining machine set and then flows through the five powder refining machine sets and the fourteen nodulizing machine sets in turn and finally out of the last nodulizing machine set; and by refining and nodulizing the powder, the spherical graphite product is obtained. The spherical graphite product has a surface closed end part structure, is spherical, and has the specific surface area of 8.0 to 12m2 / g. The number of openings on the surface of the graphite powder is 9-80 per mu m. The sphericity of the product is high; the battery capacity, the standby time and the service life are effectively increased; moreover, the preparation method can improve the yield by over 80 percent, lower the cost by 40 to 50 percent, save the power consumption by 55 percent and realize the dust recovery rate up to 100%.

Description

technical field [0001] The invention relates to a graphite powder, in particular to a method for preparing spherical graphite with a median diameter of 3-10 μm from natural flake graphite Background technique [0002] As a negative electrode material for lithium ion batteries, graphite material has the advantages of good conductivity, excellent charge and discharge voltage platform, high specific capacity and low price, so it has always been a research hotspot of negative electrode materials and has been used in commercial lithium ion batteries. widely used. Many studies have shown that the shape, crystal structure, surface structure, and impurity content of graphite particles are closely related to the lithium intercalation performance of graphite materials. However, the sources and processing processes of graphite are different, and its physical and chemical properties are also different. Therefore, in order to obtain graphite anode materials with good lithium intercalati...

AI Technical Summary

Problems solved by technology

However, due to the limitation of its preparation process, the existing spherical graphite has low production yield, high energy consumption and high cost, and the sphericity of the obtained spherical graphite is not high, the performance of the product is not ideal, and it cannot meet the needs of technological development, resulting in The charging and discharging time, standby time and service life of the battery are not ideal

When used as a power car battery, it also leads to small storage capacity, easy to overheat, low safety and practicability