Application of mixed expanded graphite serving as lithium ion battery negative electrode material

Abstract

The invention discloses application of mixed expanded graphite serving as a lithium ion battery negative electrode material. The mixed expanded graphite material is used as the lithium ion negative electrode material to prepare a lithium ion battery; according to the negative electrode material, the weight ratio of SBR (with the solid content of 50%):CMC: Super: p is 95.5:2:1.5:1, an appropriate amount of deionized water is added to blend the materials into a slurry, the slurry is coated on copper foil, the copper foil obtained after coating is dried in a vacuum drying oven for 12 h to preparethe negative electrode plate, lM LiPF6 / EC+DEC+DMC by the ratio of 1:1:1 are adopted in electrolyte of the lithium ion battery, a diaphragm is a polypropylene microporous membrane, the electrode is the lithium plate, the battery is assembled in a closed glovebox with the argon atmosphere, charge-discharge tests are conducted on the lithium ion battery at 0.1 C magnification and 5C magnification, during charge-discharge at 0.1C magnification, the first-time charge-discharge cycle charge capacity is 2018 mAh / g, during discharge at 5C magnification, and after 500 times of cycle, the capacity retention ratio is 98.4%.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and more specifically relates to the application of mixed expanded graphite as a lithium-ion battery negative electrode material. Background technique [0002] Expanded graphite is a carbon material. Using expandable graphite as raw material, when treated at high temperature (usually 700-1200°C), the substance inserted between the expanded graphite layers will decompose rapidly, and the gas generated will form a high pressure in the expandable graphite interlayer domain and expand along the c-axis direction. Expansion, bulk density from 0.7 to 1.8g / cm 3 Change to 0.003~0.03g / cm 3 , the expansion multiple is tens to hundreds of times. Due to the loose structure of expanded graphite, porous and worm-like, large surface area and high surface energy, it has excellent liquid phase adsorption performance, good plasticity, good flexibility, ductility and sealing, so it is widely used in environme...

AI Technical Summary

Problems solved by technology

[0004] Therefore, we can combine the respective advantages of the two graphites, and mix microcrystalline graphite and microcrystalline graphite together to prepare mixed expanded graphite. The obtained mixed expanded graphite will have better electrochemical properties and can also be used as a better adsorption material. , the specific surface area will also be greatly improved compared with before, and there is no research report on the technical method of preparing expanded graphite materials by mixing microcrystalline graphite and flake graphite as raw materials

At the same time, there is no technical research on the application of this material to lithium-ion battery anode materials.