Effect of Citric Acid on Electrochemical Properties of Spinel LiMn<sub>2</sub>O<sub>4</sub> Prepared by Solid-State Combustion Synthesis

Abstract

LiMn2O4 cathode materials were successfully prepared by solid-state combustion synthesis with the lithium carbonate and the manganese carbonate as raw materials and the citric acid as fuel. The effect of citric acid on composition, microstructure and electrochemical properties of LiMn2O4 cathode materials was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV) and galvanostatic charge-discharge test. The results indicated that a pure phase of LiMn2O4 was prepared at the product with 5 wt% citric acid. However, an impure phase of Mn3O4 was found at other products. The crystal size distribution was more uniform at the higher content of citric acid. The products with 5 wt% and 10 wt% citric acid, the cubic structure morphologies of which were more prominent, and the capacities of which were higher than that of bare LiMn2O4 product. Their initial discharge specific capacities were 119.6 mAh•g-1 and 114.0 mAh•g-1, and their capacity retention ratios after 40 cycles were 85.0% and 87.7%, respectively.