화학공학소재연구정보센터
Electrochimica Acta, Vol.78, 40-48, 2012
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)center dot 9H(2)O. 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), N-2 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 m(2) g(-1). The LiFePO4/C submicrofibers composite displays high initial discharge capacities of 166 and 168 mAhg(-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 degrees C. respectively. Even at high rate of 5 C, the LiFePO4/Csubmicrofibers composite delivers discharge capacities of 132 and 138 mAh g(-1) and excellent cycle performance at 25 and 55 degrees C. respectively. The results indicate that the electrospinning method is promising to prepare LiFePO4/C composite with high electrochemical performance. (C) 2012 Elsevier Ltd. All rights reserved.