Anode material for lithium-ion power battery and preparation method of anode material

Abstract

The invention discloses an anode material for a lithium-ion power battery and a preparation method of the anode material, and relates to the field of preparation of battery materials, in particular tothe field of preparation of the anode materials of lithium batteries. The anode material is characterized by being prepared from porous silicon dioxide and coating compound asphalt, wherein porous silicon dioxide is prepared from raw materials as follows: polycrystalline silicon powder, hydrochloric acid, silver carbonate, hydrofluoric acid and hydrogen peroxide; the compound asphalt is preparedfrom materials as follows: nano calcium carbonate, asphalt, graphene, sodium hydroxide, a binder and distilled water; after porous silicon dioxide and the compound asphalt are mixed uniformly in a ratio being 5:(3-5), a mixture is carbonized, and a silicon-carbon anode material is prepared. The prepared silicon-carbon composite material has the effect of improving rate performance and safety performance while the transfer number of lithium ions is increased and stacking of the lithium ions is reduced, further has advantages of high gram volume, excellent cycle performance, high liquid absorption and retaining capability, low cost and low expansion rate, and is particularly suitable for meeting demands of high-energy-density batteries for the anode material.

Description

technical field [0001] The invention relates to the field of preparation of lithium ion battery materials, in particular to the field of preparation of negative electrode materials for lithium batteries. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, long cycle life, and environmental friendliness. They have been widely used in the portable mobile electronics market, and have shown attractive application scenarios in transportation and energy storage fields such as electric vehicles and power grid peak regulation. At present, graphite-based carbon materials are mainly used as anode materials for commercial lithium-ion batteries. However, the theoretical specific capacity of graphite is only 372 mAh / g, which restricts the practical application of lithium-ion batteries as power batteries in fields such as transportation and energy storage. Therefore, it is necessary to seek negative electrode material systems with high specific...

AI Technical Summary

Problems solved by technology

[0003] Silicon-based materials such as silicon, silicon-based alloys, and silicon oxides have high theoretical specific capacity and good safety, and are ideal substitutes for commercial carbon anode materials for lithium-ion batteries. However, the large expansion rate of silicon materials limits its wide application, and at present, the expansion rate of materials is mainly reduced by means of material nanometerization and material surface modification. For example, patent CN201110378734.X discloses a silicon-carbon negative electrode material for lithium-ion batteries. The invention discloses a method for improving the cycle performance of the silicon-carbon negative electrode material. The silicon-carbon composite material is composed of graphite powder, and the mass ratio components are: 1-20% of nano-silicon powder, 1-40% of carbon material precursor, and the rest is graphite powder, but its consistency is difficult to control and its expansion coefficient is too high, resulting in poor cycle performance, and the porosity of the silicon material can not only reduce the expansion rate of the silicon material, but also combine the porous asphalt of the coating layer to reduce the silicon material. At the same time as the expansion rate of the material, the liquid absorption and retention capacity of the material can also be improved, which is a good choice, and can greatly improve the high expansion problem of silicon materials and improve its cycle performance

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