Study of Micro-Silicon Particles Covered by Graphene

Abstract

Lithium-ion batteries have become a new hot spot in battery research due to their high-energy density, environmental friendliness, and multiple charge/discharge times. Silicon-based materials have become the best choice of anode materials for lithium-ion batteries due to their advantages of low lithium insertion voltage, high specific theoretical capacity, and large reserves on the planet. However, the silicon-based material has a large volume expansion (about 300%) during cycling, which causes the active silicon to fall off from the surface of the conducting material. This expansion will also break the solid electrolyte interphase (SEI) on the surface of the silicon electrode, and will consume additional Li+, causing the battery’s capacity to drop rapidly as the times of circulation increases. In addition, the conductivity of silicon-based materials is lower than that of graphite anode, which have already been used commercially, led to the worse performance of the silicon anode. These drawbacks force silicon-based anode materials to encounter huge resistance in the commercialization process. Therefore, research on the improvement of performance of the silicon-based anode materials is of great significance.