Bismuth oxide nanoparticles embedded carbon nanofibers as self-standing anode material for Na-ion batteries

Graphite, the most commonly used anode material for lithium-ion batteries (LIBs), cannot be employed for sodium-ion batteries (SIBs) with conventional carbonate-based electrolyte since the interlayer spacing of graphite is not large enough for sodium ions to be de/intercalated. Bismuth oxide (Bi2O3) is considered as suitable alternative anode material for SIBs owing to its good theoretical specific capacity. However, the volume expansion taking place during discharge and low electrical conductivity result in poor cycling performance and fast capacity fading. Thus, composites with carbon materials are usually preferred to overcome those issues. In this work, Bi2O3 nanoparticles were incorporated in carbon nanofibers (CNF) via electrospinning method. The CNF-Bi2O3 self-standing nanocomposite anode material exhibited excellent rate capability (i.e. 504 mAh g(-1) after 100 cycles at 25 mA g(-1) current density) and superior capacity values (393 mAh g(-1) at 625 mA g(-1)).