Electrospinning fabrication and electrochemical properties of LiFePO₄/C composite nanofibers

LiFePO₄/C composite nanofibers were synthesized by calcination of the [LiOH + Fe(NO₃)₃ + H₃PO₄]/PVP electrospun nanofibers. Polyvinyl pyrrolidone (PVP) was used as the electrospinning template and carbon source. During the calcination [LiOH + Fe(NO₃)₃ + H₃PO₄] were transformed to LiFePO₄ and PVP was decomposed into carbon. The morphology and properties of the as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller (BET) specific surface area analysis, electrochemical impedance spectroscopy and galvanostatic charge–discharge measurements. The results indicate that the mean diameter of as-prepared LiFePO₄/C composite nanofibers is 179.08 ± 29.66 nm and the BET specific surface area is 66.59 m² g⁻¹. The addition of carbon does not affect the structure of LiFePO₄, but improves its electrochemical performances. At the current density of 0.2 C, the initial discharge capacity of LiFePO₄/C electrode is 133.6 mAh g⁻¹ and there is no obvious capacity fading after 100 cycles. The formation mechanism of the LiFePO₄/C composite nanofibers was also proposed.