In Situ Synthesis of LiFePO₄/Carbon Fiber Composite by Chemical Vapor Deposition with Improved Electrochemical Performance

A novel in situ route was employed to synthesize LiFePO 4 /carbon fiber (CF) composites. The route combined high-temperature solid-phase reaction and chemical vapor deposition (CVD) using LiOH·H 2 O and FePO 4 ·2H 2 O as the precursors for LiFePO 4 growth and acetylene (C 2 H 2 ) as carbon source for CF growth. The formation mechanism of the LiFePO 4 /CF composites was investigated by X-ray diffraction and scanning electron microscopy. The electrochemical performance of the composites was studied by galvanostatic cycling and cyclic voltammetry. The results showed that the in situ CF growth could be realized by the catalytic effect of the Fe 2 O 3 intermediate. The LiFePO 4 /CF composite with 450 °C CVD reaction showed the best electrochemical performance. This sample exhibited a stable discharge capacity of 122 mA h g –1 at 10C and a slow capacity fade of only 5.5% after 1170 cycles at 1C, indicating an attractive application in high-power Li ion batteries.