Molten salt synthesis and electrochemical properties of spherical LiFePO4 particles

Well-crystallized LiFePO4 was directly synthesized by the KCl molten salt (MS) method. According to this method, the pre-sintered intermediate was mixed with KCl, and then sintered at a certain temperature, which was determined by thermogravimetric analysis (TGA). The olivine structure and spherical morphology were confirmed by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The spherical products show a higher tap density, which will benefit the enhancement of volumetric energy density. The electrochemical behavior was studied by cyclic voltammetry and galvanostatic tests. The LiFePO4 product sintered at 755 °C for 3 h exhibits the best electrochemical performance. At a rate of 0.1 C, it can deliver an initial capacity of 130.3 mAh g− 1, and a capacity of 137.2 mAh g− 1 at the 40th cycle. At a high discharge rate of 5 C, it still exhibits a capacity of 92 mAh g− 1.