Sulfureted polyacrylonitrile derived carbon encapsulated silicon as high-performance anode material for lithium-ion batteries

Abstract

Silicon-based materials are the most promising anode materials for the next generation of lithium-ion batteries. However, the low conductivity, large volume effect, and continuous formation of solid-electrolyte-interface (SEI) film; resulted in low rate-capability, severe electrode pulverization, and aerogenesis, which hinders their practical application. To enhance the electrochemical performance of silicon-based materials, in this work, sulfur-doped carbon derived from sulfurized polyacrylonitrile is used as a carbon matrix for confining and encapsulating nano silicon particles. It is found that sulfur doping can effectively enhance the cycle stability of the silicon-based composite. The as-prepared silicon/sulfur-doped carbon composite with a moderate silicon content (∼16.7 wt%) exhibits an initial discharge capacity of 1735 mAh g−1 and is maintained at 699 mAh g−1 after 200 cycles. Even at the current density of 1 A g−1, the 0.5gSi@SPANdC composite also exhibits good cycle stability and a relatively high reversible capacity of 546.1mAh g−1 after 400 cycles.