Hydrothermally enhanced MnO/reduced graphite oxide composite anode materials for high performance lithium-ion batteries
Nanoplate-assembled MnO2 spheres with a high surface area are synthesized and act as a manganese precursor for the hydrothermal process to synthesize MnO/reduced graphite oxide (MnO/RGO) composite powders. The structures and electrochemical properties of the obtained samples are studied by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, thermal gravimetry, N2 adsorption/desorption measurement and galvanostatic cell cycling. The content of the reduced graphite oxide and the use of the reducing agent (N2H4) are found to play important roles to determine the structures and properties of the MnO/RGO products. The MnO/RGO composites contain a uniform RGO coating and possess a high specific surface area of up to 42.4 m2 g-1. As an anode material for rechargeable lithium batteries, such a MnO/RGO composite can achieve excellent high rate capability and cycling stability. The composite with 13.19 wt% RGO shows the optimal electrochemical performance and can deliver reversible capacities of 855, 842, 821, 737 and 630 mAh g-1 at the current densities of 0.16, 0.4, 0.8, 1.6 and 3.2 A g-1, respectively.