Hexagonal Sb Nanocrystals as High-Capacity and Long-Cycle Anode Materials for Sodium-Ion Batteries

Antimony (Sb) is regarded as a promising anode materialfor sodiumion batteries (SIBs) on account of its high theoretical specific capacity(similar to 660 mAh g(-1)) and low cost. However, thelarge volume expansion (similar to 390%) during charging has inhibitedits practical application. Herein, hexagonal Sb nanocrystals encapsulatedby P/N-co-doped carbon nanofibers (Sb@P-N/C) were prepared using alow-cost but mass-produced electrospinning method. The as-preparedSb@P-N/C, used as anode material for SIBs, exhibits unexpected cyclingstability and rate capability, with 500.1 mAh g(-1) at 50 mA g(-1) after 200 cycles and 295.6 mAh g(-1) at 500 mA g(-1) after 400 cycles.Especially, the full battery fabricated by Na (Ni1/3Fe1/3Mn1/3) O-2 || Sb@P-N/C possesses areversible specific capacity of 66.8 mAh g(-1) at50 mA g(-1) over 60 cycles. This simple and low-costfabrication technology combined with unique crystal morphology offersnew strategies for the advancement of sodium ion batteries (SIBs)in energy storage and electrical transportation.