4. Conclusions
In summary, we have demonstrated a solid-state combustion method to synthesize single-phase spinel LiMn2O4cathode mate-rials based on a two-stage calcination progress, in which, the temperature of the second stage plays a key role in the structure and physicochemical properties of the obtained LiMn2O4products.During the successful synthesis progress of LiMn2O4, the weight loss occurs in three temperature regions. When further calcination temperature was performed lower than 700 C, the diffraction peaks of all the combustionproducts are identified as a single phase of cubic spinel structure with the space group Fd3m. Compared with other conditions, the as-prepared LiMn2O4 powders which experienced the second-stage, and calcined at 700 C is the most uniform, and the charge transfer resistance (Rct) is the lowest,
accompanying the best electrochemical activity and highest discharge capacity. Its initial discharge specific capacity is
119.1 mA h/g and the discharge capacity retention remains 87.2% after 50 cycles. A comparison of solid-state combustion reaction sample B700and the solid-state reaction sample C700at the same calcination temperature and time displays better electrochemical performance. Meanwhile, a comparison of sample B700 and the traditional solid-state reaction of Fu et al. [27] reported in their paper shows Spinel LiMn2O4powders can be obtained by the solid-state combustion method in a short time. Therefore, this method is time and energy saving, and is promising for commercial application.