Synthesis of Porous LiFePO4/C Composite Materials by CCVD Method

Porous LiFePO4/C composite was in-situ prepared by a catalytic chemical vapor decompositon (CCVD) method in a fluidized bed reactor, using ethyne as carbon source, ferrum as catalyst, and nano-FePO4 as reactant. The composite was analyzed and characterzed by BET, SEM, CHON organic element analyzer and XRD. Results show that the composite possesses a continuous three-dimensional conductive network, high specific surface area and hierarchical multimodal porous subsphere structure. Its carbon content is 4.42 wt%, which is less than that by the conventional method. The porous LiFePO4/C composite shows the discharge capacities of 147, 141, 126 and 110 mAh·g−1 at rates of 0.1, 1.0, 5.0 and 10 C, respectively, gaining better high rate charge-discharge performance. In addition, the discharge capacity of porous LiFePO4/C composite rarely loses at 1 C rate after 80 cycles, which exhibits better cycling performance than that of traditional carbon coated LiFePO4.