An Improved Method to Prepare FePO₄ by Introduction of Na₃PO₄ and Its Usage for Fabricating LiFePO₄

Abstract

A LiFePO₄/C composite was synthesized by a simple solid-state reaction method using glucose as reductive agent and carbon source and FePO₄ as precursor, which was prepared by introduction of Na₃PO₄ as phosphorus source and pH regulator in order to pursue lower cost and environmental protection. The structure and morphology of FePO₄ and LiFePO₄/C were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Furthermore, electrochemical performance of LiFePO₄/C was investigated by galvanostatic charge–discharge tests and cyclicvoltammogram (CV). The results indicate that FePO₄ obtained has a small particle size and uniform particle distribution, which is demonstrated to be applicable as the iron source to synthesize LiFePO₄/C. Prepared LiFePO₄/C shows an excellent rate capability and cycle performance. At rates of 0.1 C, 0.2 C, 1 C and 2 C, the initial discharge capacities of 161, 158, 145 and 120 mAh/g were achieved, respectively and the discharge capacity is 154, 153, 140 and 116 mAh/g after 400 cycles. The employed method of preparing FePO₄ by introduction of Na₃PO₄ has advantages such as low cost, safe raw material, environmental benign and recyclable products, which is suitable for industrial production.

Keywords

lithium ion batteries / cathode / LiFePO₄ / FePO₄

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