Progress in modification of micron silicon-based anode materials for lithium-ion battery

The abundant silicon-based anode materials are considered as one of the preferred materials for the next generation high energy density lithium-ion batteries (LIBs) due to the high theoretical capacity. However, the low intrinsic conductivity and the great volume expansion during charging/discharging for silicon-based anode induce the crushing of active materials, excessive thickening of the solid electrolyte interface (SEI), and loss of electrical contact with the collector, resulting in battery capacity fading. The promising nano-silicon is facing high production costs, low tap density, and high interfacial reactivity, which severely limits the practical application of silicon-based anode materials. In this case, micron silicon-based anode materials have received attention again. This review first illustrates the advantages and challenges of micron silicon-based anode materials compared with nano silicon, and explores the reasons for the failure of micron silicon-based anode materials. The modification measures such as interfacial coating, microstructure, and elemental doping were systematically summarized. It is concluded that synergistic multiple strategies of carbon materials, more flexible polymers or oxides coatings core-shell combination with cage-like structure, urchin-like, and scallop-like, etc. designs can improve the mechanical strength and electrical properties of micro‑silicon anodes effectively by constructing dynamic conductive networks and buffer voids and employing cheaper raw materials and synthesis processes to achieve large-scale commercialization applications of micron silicon-based anodes in the future.