Effect of the particle size on the electrochemical performance of nano-Li2FeSiO4/C composites

Nano-Li 2 FeSiO 4 /C composites were prepared from three kinds of nano-SiO 2 (their particle sizes are 15 ± 5, 30 ± 5, and 50 ± 5 nm, respectively) by a traditional solid-state reaction method. The as-prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), elementary analyzer, Brunauer–Emmett–Teller (BET) analysis, galvanostatic charge–discharge test, and electrochemical impedance spectroscopy. XRD results reveal that nano-Li 2 FeSiO 4 composites fabricated from nano-SiO 2 (smaller than 30 nm) have less impurity. SEM results indicate that the particle size of nano-Li 2 FeSiO 4 composites is nearly accord with the particle size of nano-SiO 2 . BET analysis indicates that the specific surface areas of LFS15, LFS30, and LFS50 are 35.10, 35.27, and 26.68 m 2 g, respectively, and the main pore size distribution of LFS15, LFS30, and LFS50 are 1.5, 5.5, and 10 nm, respectively. Electrochemical measurements indicate that nano-Li 2 FeSiO 4 composites prepared from nano-SiO 2 of 30 ± 5 nm have the best electrochemical performance among the three samples.