Effects of Spray Drying Conditions on Morphology and Performance of Nano/Micro Structure LiFePO₄/C

Abstract

The nano/micro LiFePO4/C composite was prepared by a wet milling-spray drying-carbothermal reduction process. The structure and morphology were characterized by X-ray diffraction (XRD) and electron scanning microscope(SEM), electrochemical properties were characterized by cyclic voltammetry,AC impedance testing with galvanostatic charge-discharge method to investigate the influence under different spray drying conditions. The results show that the morpholoyy and electrochemical performance are significantly influenced by slurry concentration, inlet temperature and feed rate, while are mildly influenced by nozzle diameter. The morphology of the obtained sample is transformed from bowl-like mesoporous structure to spheres with the decrease of the slurry concentration. With a slurry concentration of 200g/L, an inlet temperature of 200℃, a feed rate of 1.3L/h and a spray nozzle diameter of 0.5mm, the obtained sample has the best electrochemical properties. Under that condition, the discharge capacities at 0.5C and 10C under room-temperature are 160mAh·g-1 and 123mAh·g-1, respectively, and no obvious capacity fading is observed after 100 cycles.

Keywords

• LiFePO₄/C
• nano/micro structure
• cathode material
• spray drying