Combustion-synthesized LiNi0.6Mn0.2Co0.2O2 as cathode material for lithium ion batteries

Abstract

A nitrate/urea mixture was used as fuel to simply combustion-synthesize LiNi0.6Co0.2Mn0.2O2 as a high-capacity cathode material for lithium ion batteries. The reaction formulas and physical properties of the resultant cathode materials sintered at various temperatures were examined using thermogravimetric analysis/simultaneous differential thermal analysis, X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectrometry, and inductively coupled plasma/atomic emission spectrometry. The influence of sintering temperature on the electrochemical performance was evaluated by analyzing the charge/discharge profiles and cycling and rate-capability performances. The LiNi0.6Co0.2Mn0.2O2 cathode sintered at 800 degrees C exhibited a discharge capacity of 170 mA h g(-1) measured at a constant 20 mA g(-1), 98.2% capacity retention after 30 cycles, and better rate capability than the cathodes sintered at 700, 900, and 1000 degrees C. The experimental results suggest that the enhanced electrochemical performance of the LiNi0.6Co0.2Mn0.2O2 cathode sintered at 800 degrees C is attributable to the pure, well-organized layered structure containing few mixed cations and to the shorter diffusion path resulting from the uniformly distributed nanoparticles.