Hierarchical α-MnO2 nanowires as an efficient anode material for rechargeable lithium-ion batteries

In this work, a bulk quantity of alpha-MnO2 hierarchical nanowires was synthesized by a facile redox reaction between potassium permanganate (KMnO4) and glycine under ambient conditions. The physicochemical characterization results revealed that the MnO2 sample exhibited highly uniform (1D) nanowire morphology and unique surface texture features such as a high specific surface area of 181 m(2) g(-1) with a beneficial mesoporous structure. Taking the advantage of hierarchical 1D nanowires morphology and improved microstructural properties, a cell with MnO2 nanowires as an anode showed relatively good electrochemical performance with enhanced lithiation degree and improved cycling stability. The initial discharge capacity of as high as 1373 mA h g(-1) was achieved at 100 mA g(-1) and rendered a reversible capacity of 735 mA h g(-1) even after 100 cycles with an average Coulombic efficiency of 97%. The improved electrochemical performance of alpha-MnO2 is attributed to its hierarchical nanowire morphology and enriched textural surface properties, which provide a good Li-ion diffusion path, large electrode-electrolyte contact area and effective accommodation of the strain generated from volume expansion during repeated lithiation/delithiation processes.