Boosting electrochemical performance of electrospun silicon-based anode materials for lithium-ion battery by surface coating a second layer of carbon

摘要

Electrospun carbon nanofibers (CNFs) encapsulated Si nanoparticles (Si NPs) are effective anode materials for lithium-ion batteries (LIBs), however, the cycle stability is poor due to the volume expansion of Si NPs during charging/discharging. We herein report a strategy to further improve the cycle stability by coating a second layer of carbon on the surface of CNFs/Si nanofibers. The secondary carbon coated composite nanofibers (CNFs/Si@ C) were produced by growing a layer of polyaniline (PANI) on the surface of electrospun CNFs/Si nanofibers followed by high-temperature pyrolysis. The CNFs/Si@ C material demonstrated a specific capacity of 936.1 mAh g(-1) at the first discharge cycle and 753.5 mAh g(-1) at the 100th cycle, which has a retention rate of 80.5%, much higher than that of the pristine CNFs/Si. Obviously, the secondary carbon coating strategy is effective to promote the cycle stability of Si-based anode materials.