Controlled Synthesis of Manganese Oxyhydroxide Nanotubes: Implications for High‐Efficiency Supercapacitors

Successful attempts have been made to control the synthesis of tubular MnOOH with nanodimensions on high electronic conductivity graphite felt (GF) to be used as a flexible supercapacitor electrode. As a fundamental study, the time‐dependent kinetics was investigated to interpret its formation mechanism, which can be depicted as the curling of a two‐dimensional precursor into a one‐dimensional structure with a hollow interior. As a result of the nanotube structure, the active surface area of MnOOH is completely accessible to electrolyte ions and has a shorter charge‐transport length and greater ability to withstand structural deformation. Hence, hollow‐structured MnOOH shows great promise as an electrochemical system, which is reflected in its high specific capacitance of 1156 F g −1 at 1 A g −1 . Furthermore, the high energy density of 1125 W h kg −1 and power density of 5.05 kW kg −1 reveal the outstanding energy‐storage behavior of the MnOOH/GF composites as flexible supercapacitor electrodes.