Application of spherical microcrystal graphite as lithium ion battery negative electrode material

Abstract

The invention relates to application of spherical microcrystal graphite as a lithium ion battery negative electrode material. According to the application, a spherical microcrystal graphite material serves as a lithium ion negative electrode material to prepare a lithium ion battery, wherein the weight ratio of the negative electrode material to SBR (solid content is 50%), CMC and Super-p is 96:2:1:1, then moderate deionized water is added to be mixed into slurry, the mixture is applied on copper foil and dried for 15 hours in a vacuum drying box to prepare a negative electrode piece, the bathsolution of the lithium ion battery adopts 1 milliliter of LiPF6 / EC, DEC and DMC which ratio is 1:1:1, the membrane is a polypropylene micro-porous membrane, the counter electrode is a lithium piece,and the battery is assembled in a glove box under a closed argon atmosphere. When the lithium ion battery is charged and discharged at a rate of 0.1 C, the first charge-discharge cycle charging capacity is 392 milli-amperes per gram, and when the lithium ion battery is charged and discharged at a rate of 5 C, the capacity retention rate is 97.9% after being repeated for 500 times.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, and more specifically relates to the application of spherical microcrystalline graphite as a negative electrode material of lithium ion batteries. Background technique [0002] Microcrystalline graphite is a polycrystal formed by the aggregation of small crystal grains. The crystal grain size is less than 1 μm and is isotropic. The raw ore has high grade and the carbon content is generally 50-90%. The Lutang mining area in Chenzhou City is the most important graphite mining area in my country. It is known as the "Graphite Capital". The reserves of microcrystalline graphite account for 74.7% of the national microcrystalline graphite reserves, ranking first in the country, and the fixed carbon content is high. Its graphite products enjoy a good reputation at home and abroad. In recent years, the breakthrough development of microcrystalline graphite purification technology, the carbon content of...

AI Technical Summary

Problems solved by technology

However, due to the limitations of the preparation process of the existing spherical graphite, the processing efficiency of the pulverizer in the shaping process is generally not high, resulting in the low sphericity of the spherical graphite and the unsatisfactory performance of the product, which cannot meet the needs of technological development.

The prior art usually adopts a multi-stage shaping method to prepare spherical graphite. Although this method improves the defect of low efficiency of the pulverizer to a certain extent, there are many equipments, the production process is complicated, and the shape and particle size of the graphite particles are not satisfactory. to better control

On the other hand, the traditional purification process usually uses acidic aqueous solution to treat spherical graphite alone, which takes a long time and has poor results, resulting in low purity of spherical graphite produced, which seriously affects the electrochemical performance of spherical graphite as a negative electrode material.