A novel synthesis and characterization of LiFePO₄ and LiFePO₄C as a cathode material for lithium-ion battery

By Miao, Cui; Bai, Peifeng; Jiang, Qianqian; Sun, Shuqing & Wang, Xingyao
Published in Journal of Power Sources NULL 2014

Abstract

A novel hydrothermal stripping technique is developed to synthesize pure LiFePO₄ and LiFePO₄/C cathode materials. The pure sample is directly synthesized by the cation exchange between the organic phase which is prepared with FeSO₄·7H₂O and naphthenic acid, and aqueous phase prepared with H₃PO₄ and LiOH. SEM exhibits that the primary sizes of the well-distributed LiFePO₄ and LiFePO₄/C particles are about 150 nm and 100 nm in diameter, respectively. TEM indicates the LiFePO₄/C is uniformly coated with a carbon layer about 2.7 nm in size. The as-prepared LiFePO₄ exhibits a high initial discharge capacity of 135.5 mAh g⁻¹ at 0.1 C, and the LiFePO₄/C composite sintered at 650 °C for 4 h exhibits the best electrode properties with discharge capacities of 151.7, 154.8, 149.8 and 139.1 mAh g⁻¹ at 0.1 C, 0.2 C, 0.5 C and 1.0 C rates, respectively. In addition, the LiFePO₄/C also shows excellent capacity retention and cycle performances.

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