The Size Effects of Si Particles on the Final Si@C Composite Anode

The particle size of Si raw materials is closely related with the stability and the cost of the final Si-based anode. Nevertheless, the detailed mechanism is still unclear. In the present study, Si particles with different sizes (100 and 500 nm and 1 mu m) were used to prepare a nanoporous Si@C (P-Si-C) anode via Si-Mg alloy intermediate and carbon coating with Mg reduction of CO2. Contrary to the general idea, we found that P-Si-C synthesized with larger particle size of silicon exhibited better performance, and P-Si-C (1 mu m) could maintain a specific capacity of 1741.1 mAh/g after 70 cycles at a current density of 0.5 A/g, with a capacity retention rate of 81.2%. It enlightens us that silicon-carbon composites can be prepared with low-cost large-grained silicon, which has significant guidance for industrial applications.

Automated summary

In this study, it was found that nanoporous Si@C anodes prepared using larger particle size silicon exhibited better performance, providing significant guidance for industrial applications.