Synthesis of LiFePO4/polyacenes using iron oxyhydroxide as an iron source

LiFePO4/polyacenes (PAS) composite is synthesized by iron oxyhydroxide as a new raw material and phenol-formaldehyde resin as both reducing agent and carbon source. The mechanism of the reaction is outlined by the analysis of XRD, FTIR as well as TG/DSC. The results show that the formation of LiFePO4 is started at 300 degrees C, and above 550 degrees C, the product can be mainly ascribed to olivine LiFePO4. The electrochemical properties of the synthesized composites are investigated by charge-discharge tests. It is found that the prepared sample at 750 degrees C (S750) has a better electrochemical performance than samples prepared at other temperatures. A discharge capacity of 158 mAh g(-1) is delivered at 0.2 C. Under high discharge rate of 10 C, a discharge capacity of 145 mAh g(-1) and good capacity retention of 93% after 800 cycles are achieved. The morphology of S750 and PAS distribution in it are investigated by SEM and TEM. (C) 2009 Elsevier B.V. All rights reserved.