LiFePO4∕Polyacene Nanocomposite Synthesized from a Pretreatment of Iron Phosphate: In-situ Polymerization with Phenolic-Formaldehyde Resin

Abstract

Nanosized LiFePO4 particles coated by uniform thin polyacene layer are synthesized from a pretreatment of FePO4·2H2O. The polyacene layer arises from carbonization of the phenolic-formaldehyde resin which is in situ polymerization to coat the amorphous FePO4·2H2O. The particle sizes of the LiFePO4 /polyacene nanocomposite are in the range of 20−60 nm. This LiFePO4/polyacene nanocomposite delivers discharge capacities of 142, 135, 124, 110 and 80 mAh g−1 at 1 C, 2 C, 5 C, 10 C and 20 C, respectively. The cyclic voltammetry curve and electrochemical impedance spectroscopy reveal low polarization of LiFePO4/polyacene due to the complete coating of polyacene layer on the nanosized LiFePO4 particles. Also the LiFePO4/polyacene nanocomposite shows good electrochemical performances in a wide temperature ranging from −20°C to 60°C.