Preparation and electrochemical characteristics of a polyvinylpyrrolidone-stabilized Si/carbon composite nanofiber anode for a lithium ion battery

Si/carbon composite nanofibers are prepared by electrospinning a blend solution of polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), and Si particles in N,N-dimethylformamide (DMF) and then carbonizing at 800 °C. These composite nanofibers deliver more than 1000 mA g−1 of reversible capacity for 30 cycles at 200 mA g−1 current density and also maintain clear fibrous morphology, sustaining this topology even after 50 charge/discharge cycles. The addition of PVP generates a higher reversible capacity and better capacity retention compared with the Si/carbon composite nano-fiber control. These results can be ascribed to the improved dispersion of Si nanoparticles that are stabilized by PVP and the buffer effects of the amorphous carbon layer, which hinders the Si expansion during the charging.