Solution combustion synthesis of hierarchical porous LiFePO4 powders as cathode materials for lithium-ion batteries

Abstract

Hierarchical porous LiFePO4 powders were prepared by solution combustion method using a mixture of cetyltrimethylammonium bromide (CTAB) and glycine as fuel. The effects of fuel contents on structural, microstructural, and electrochemical properties were studied by various characterization methods such as X-ray diffraction, infrared spectroscopy, scanning electron microscopy, N2 adsorption–desorption isotherms, and galvanostatic charge/discharge. Single phase LiFePO4 powders were crystallized by calcination at 700 °C. Phase evolution was depended on the nature and amount of intermediate phases. The hierarchical porous microstructure was obtained at an appropriate amount of mixed fuels. LiFePO4 powders showed the high specific discharge capacity of 110 mAh g−1 and high capacity retention of 98% at 1C which were attributed to their high crystallinity and high specific surface areas. The porous microstructure and small particle size were benefitted for the electrode kinetics, as indicated by electrochemical impedance spectroscopy.