Electrochemical performance of electrospun LiFePO4/C submicrofibers composite cathode material for lithium ion batteries

A LiFePO4/C submicrofibers composite was prepared by a facile electrospinning method using LiNO3, Fe(NO3)3·9H2O, NH4H2PO4, citric acid and poly(4-vinyl)pyridine (PVP) as raw materials, and its physical properties and electrochemical performance were investigated by X-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), transmission electron microscope (TEM), energy dispersive analysis of X-ray (EDAX), N2 adsorption/desorption measurement and electrochemical tests. The crystal size of LiFePO4 fibers is about 30 nm calculated by Debye-Scherrer equation and the LiFePO4 nanofibers aggregate to LiFePO4/C submicrofibers composite with diameters of about 270–372 nm. The LiFePO4 submicrofibers are covered by an amorphous carbon layer with a thickness of about 2.6 nm and the LiFePO4/C submicrofibers composite with mesopores exhibits amazing high surface area of 167.729 m2 g−1. The LiFePO4/C submicrofibers composite displays high initial discharge capacities of 166 and 168 mAh g−1 and excellent cycle performance at 0.1 C (17 mAh g−1) in the voltage range of 2.5–4.5 V at 25 and 55 °C, respectively. Even at high rate of 5 C, the LiFePO4/C submicrofibers composite delivers discharge capacities of 132 and 138 mAh g−1 and excellent cycle performance at 25 and 55 °C, respectively. The results indicate that the electrospinning method is promising to prepare LiFePO4/C composite with high electrochemical performance.

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► LiFePO4/C submicrofibers composite was prepared by an electrospinning method. The diameters of LiFePO4/C submicrofibers are about 270–372 nm.
► The submicrofibers composite with mesopores exhibits surface area of 167.729 m2 g−1. This composite shows high discharge capacity of 166 mAh g−1 at 0.1 C at 25 °C.
► The composite still delivers capacity of 132 mAh g−1 and better cyclability at 5 C.