Superior performance of LiFePO4/C with porous structure synthesized by an in situ polymerization restriction method for lithium ion batteries

A porous LiFePO4/C nanocomposite was synthesized by an in situ polymerization restriction method. The obtained product possessed higher surface area and abundant pore structure. The physical and electrochemical properties of the LiFePO4/C composite were investigated by X-ray diffraction, thermogravimetry analysis, nitrogen adsorption-desorption measurement, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy and electrochemical measurements. Electrochemical test indicated that the discharge capacity of LiFePO4/C was as high as 156.1 mAh g−1 in the first cycle at 0.5C and 145.2 mAh g−1 after 50 cycles. The initial discharge capacities of the electrodes exhibited 126.3 mAh g−1, 108.6 mAh g−1, 82.5 mAh g−1 and 62.8 mAh g−1 at the high rates of 5C, 10C, 20C and 50C. The discharge capacity retentions after 500 cycles were 94.4%, 90.6%, 87.8% and 90.9% of the initial discharge capacity at rates of 5C, 10C, 20C and 50C, respectively.