Preparation technology of silicon-carbon composite negative electrode material

Abstract

The invention relates to a preparation technology of a silicon-carbon composite negative electrode material. In the preparation technology, a coated modified auxiliary material is used as high-purityindustrial silicon, and a graphite main material is low-ash anthracite. Through innovative adoption of glucose coating carbonization, a coating material is approximately nanocrystalized, so that a coating layer is formed more perfectly and uniformly; fluorocarbon resin is used, fluorine is an element with unique and stable properties, and in the periodic table, fluorine has the strongest electronegativity and the lowest polarizability and has the atomic radius is second only to that of hydrogen; therefore, C-F bonds are very difficultly destroyed by light, heat, electrochemical factors and thelike, F atoms have more negative charges, the adjacent fluorine atoms are mutually exclusive, the fluorine atoms on a fluorine-containing hydrocarbon chain are spirally distributed along C-C bonds ofgraphite, and peripheries of the C-C bonds are surrounded by the fluorine atoms to form a highly-stable three-dimensional protection barrier to protect the stability of the graphite, so that the graphite structure in the charge and discharge process of a lithium battery is improved and the cycle life is increased; the first-time capacity of the industrial silicon is lower by 1500-2000mah / g.

Description

technical field [0001] The invention relates to a preparation process of a silicon-carbon composite negative electrode material, belonging to the technical field of material preparation. Background technique [0002] With the continuous improvement of the mileage requirements of new energy vehicles in practical applications, the current material system is obviously unable to meet the actual needs, and the development of new high-energy and high-performance materials is imminent. At present, silicon-based materials have become the most preferred choice for battery companies and lithium battery material manufacturers to improve negative electrodes. The status quo is that most of the material suppliers have launched the research and production of silicon-carbon composite materials as anode materials. At present, only 1-2 anode giants have entered the stage of pilot mass production, and most material suppliers are still in the process of research and development. [0003] Add n...

AI Technical Summary

Problems solved by technology

[0003] Add nano-silicon to the negative electrode material to form a silicon-carbon negative electrode. The high-purity nano-silicon powder is ground into 5-50nm by a sand mill. The cost is too high. The market price is 2,000 yuan / kg. At this stage, new energy vehicles require a lot of batteries. Enterprises reduce costs, the cost is too high and large-scale application is difficult to commercialize

Images