A simple, low-cost and eco-friendly approach to synthesize single-crystalline LiMn2O4 nanorods with high electrochemical performance for lithium-ion batteries

The single-crystalline LiMn2O4 nanorods were successfully synthesized by a simple, low-cost and eco-friendly approach in which the γ-MnOOH nanorods were prepared through a facile hydrothermal process, in which KMnO4 was reduced by anhydrous alcohol (CH3CH2OH) without adding any template reagent or additional surfactant. The crystal structures and morphologies of synthesized materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. The results showed that the γ-MnOOH nanorods had high crystallinity and well-shaped morphology with an average diameter of 200 nm and an average length of 12 μm. For the resulting LiMn2O4 nanorods, the electrochemical properties were investigated by galvanostatic charge-discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). For the optimal LiMn2O4 nanorods, the initial discharge capacity was 123.5 mAh g−1 and remained 110.2 mAh g−1 after 100 cycles at 1.0 C in the voltage range of 3.20∼4.35 V. Moreover, the optimal LiMn2O4 nanorods can present superior rate performance, especially the capacity recovery performance as the charge-discharge rate restores to 0.1 C from 5.0 C. Such excellent electrochemical performance could make them to be the promising cathode material for high performance lithium-ion batteries.