Facile coating of micron/submicron Si with N-doped porous carbons to yield Si/C composites with good long-cycle stability

Si/C composite is a promising anode material for high-energy-density lithium ion battery. However, preparing Si/C with good long cycle performance (＞400 cycles) from micron/submicron Si was rarely reported. In this study, Si/C composites were prepared by coating rice-husk-based micron/submicron Si with N-doped porous carbon; the coating was achieved via ball milling of the Si, melamine, and glucose before carbonization. The yielded composite showed a specific capacity of 1062.7 mAh/g at 0.5 A/g after 800 cycles. Such a long-cycle performance was rare for previously-reported Si/C composites derived from micron/submicron Si. The good performance was ascribable to the sufficient coverage of surface Si with N-doped porous carbons. Additionally, the process for conversion of micron/submicron Si was rather simple, in that it did not use expensive feedstocks, complicated equipment, or complex synthesis steps. The process was industrially promising in conversion of micron/submicron Si into Si/C composite with good long-cycle stability. •Micron/submicron Si was converted into Si/C by a simple method.•The method needs no complicated equipment or complex conversion steps.•The obtained Si/C showed superior long-cycle capacity compared with reported Si/C.•The capacity at 0.5 A/g after 800 cycles was as high as 1062.7 mAh/g.