Facile controlled synthesis of MnO2 nanostructures for high-performance anodes in lithium-ion batteries

At present, new electrode materials still need to be developed to enhance the energy density, cyclability, initial coulombic efficiency and rate capability of lithium-ion batteries (LIBs). Here, we report a simple, rapid, cost-effective and novel technology to prepare MnO2 through the decomposition of KMnO4 under different pH values without surfactants or high temperatures. Moreover, the formation mechanisms of curly MnO2 nanosheets, flower-like MnO2 and onion-like MnO2 are analyzed in depth. The great variation in the electrochemical performance of MnO2 prepared under different pH values clearly indicates the importance of the nanostructure. Furthermore, curly MnO2 nanoflakes fabricated at pH 2 (pH2-MnO2) show good initial coulombic efficiency (ca. 80%) and long cyclability (ca. 1038 mAh g−1 over 150 cycles), which is attributed to their relatively large surface area and stable structure.