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