Preparation method of micron-sized porous hollow silicon spheres

Abstract

The invention discloses a preparation method of micron-sized porous hollow silicon spheres, and belongs to the technical field of preparation of micro-nano spherical materials. The preparation methodspecifically comprises the following steps: firstly, putting magnesium powder into an absolute ethyl alcohol solution of 3-mercaptopropyltriethoxysilane, magnetically stirring, and centrifugally drying; putting the modified magnesium powder into a mixed solution of deionized water, absolute ethyl alcohol and ammonia water, performing magnetic stirring, adding tetraethoxysilane, performing continuous magnetic stirring, and performing suction filtration and drying to obtain pretreated magnesium powder; putting the pretreated magnesium powder into a mixed solution of deionized water and absoluteethyl alcohol, continuously dropwise adding ammonia water and tetraethoxysilane into the mixed solution, continuously and magnetically stirring, and finally, carrying out suction filtration and dryingto obtain magnesium powder coated silicon dioxide microsphere powder; and carrying out acid etching, drying and the like on the obtained powder to obtain the porous hollow silicon spheres. The silicon with the porous hollow structure prepared by the method disclosed by the invention provides an internal buffer space for a volume expansion effect appearing when a silicon-based lithium ion batteryis applied in the future, so that the expansion probability of silicon particles is reduced, and the cyclic stability of a battery is improved.

Description

technical field [0001] The invention relates to a method for preparing micron-scale porous hollow silicon spheres, and belongs to the technical field of preparation of micro-nano spherical materials. Background technique [0002] Silicon is regarded as the most potential anode material for next-generation lithium batteries because of its high theoretical capacity and low working voltage. However, during the charging / discharging process of silicon-based lithium batteries, Li + During the insertion / extraction process, the volume expansion / contraction of the material produces an irreversible volume change, repeated volume expansion / contraction, resulting in the cracking and crushing of the silicon negative electrode, and the huge volume expansion of silicon during the charge and discharge process, which in turn limits its application. . Contents of the invention [0003] The purpose of the present invention is to provide a preparation method of micron-scale porous hollow si...

AI Technical Summary

Problems solved by technology

However, during the charging / discharging process of silicon-based lithium batteries, Li + During the insertion / extraction process, the volume expansion / contraction of the material produces an irreversible volume change, repeated volume expansion / contraction, resulting in the cracking and crushing of the silicon negative electrode, and the huge volume expansion of silicon during the charge and discharge process, which in turn limits its application.

Images