High energy ball milling method for silicon-based anode materials with porous structure research

In this study, a porous silicon anode material was designed to solve the problems of electrode deformation and electrical contact loss caused by volume expansion during the use of silicon anode material. Silicon-aluminum composite powder prepared by high-energy ball milling method, after Al is removed by chemical etching, Si particles show larger specific surface and porosity, and the larger pores provide a certain buffer space for the volume expansion of silicon during lithium intercalation, which can better release stress during the volume expansion, so that it has better cycle performance and higher capacity retention rate. The results showed that the porous Si anode was prepared by ball milling Si-Al powder for 12 h, and the first charge specific capacity was 2912.9 mAh/g at 200 mAh/g current density, and the coulombic efficiency was 83.91%. After 100 cycles at 400 mA/g current density, the capacity retention rate was 34.6% compared with the fourth cycle. This paper provides a new idea for the industrialization of porous silicon.