Effects of different iron sources on the performance of LiFePO₄/C composite cathode materials

Fei Gao1) , Zhiyuan Tang1), and Jianjun Xue2) 1) School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China 2) Great Power Battery Co. Ltd., Guangzhou 511483, China

摘 要：Olivine LiFePO4/C composite cathode materials were synthesized by a solid state method in N2 + 5vol% H2 atmosphere. The effects of different iron sources, including Fe（OH）3 and FeC2O4·2H2O, on the performance of as-synthesized cathode materials were investigated and the causes were also analyzed. The crystal structure, the morphology, and the electrochemical performance of the prepared samples were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, laser particle-size distribution measurement, and other electrochemical techniques. The results demonstrate that the LiFePO4/C materials obtained from Fe（OH）3 at 800°C and FeC2O4·2H2O at 700°C have the similar electrochemical performances. The initial discharge capacities of LiFePO4/C synthesized from Fe（OH）3 and FeC2O4·2H2O are 134.5 mAh·g-1 and 137.4 mAh·g-1 at the C/5 rate, respectively. How-ever, the tap density of the LiFePO4/C materials obtained from Fe（OH）3 are higher, which is significant for the improvement of the capacity of the battery.

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