Flexible freestanding 3D Si/C composite nanofiber film fabricated using the electrospinning technique for lithium-ion batteries anode

Abstract

Flexible freestanding three-dimensional (3D) Si/C nanofiber composite film was fabricated using electrospinning technique. The physical properties of 3D Si/C nanofiber composite film were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TG) and nitrogen adsorption-desorption measurements. The electrochemical performances were studied by galvanostatic discharge/charge cycles, cycle voltammograms (CVs) and electrochemical impedance spectra (EIS). The results indicate that Si nanoparticles can be uniformly encapsulated in the interior of carbon nanofibers to form 3D nanofiber film. At 0.1 C, the discharge capacity of 3D Si/C nanofiber composite film in 2nd cycle is 1620 mAh g−1 and the capacity loss rate for per cycle is 0.0259% from 2nd to 500th cycles, exhibiting the excellent electrochemical stability. The researched results prove that carbon nanofiber film can impede the accumulation, accommodate the volume expansion and strength charge transport of Si nanoparticles during charge/discharge cycle. As-synthesized Si/C nanofiber composite film is a potential lithium-ion batteries anode.