Template-Assisted Synthesis of Porous Manganese Dioxide Hollow Rods as Supercapacitor Electrode Material

We propose a facile template strategy for fabrication of porous δ manganese dioxide (δ-MnO2) hollow rods under mild conditions. First, highly dispersible molybdenum oxide (MoO3) rods were hydrothermally prepared. Next, MoO3/carbon (MoO3/C) composite rods were further synthesized by wrapping a MoO3 substrate with a polypyrrole thin layer through the oxidative polymerization of pyrrole, followed by annealing in an inert atmosphere. Finally, porous δ-MnO2 hollow rods were produced by redox reaction between the carbon component of MoO3/C and potassium permanganate (KMnO4), followed by total dissolution of MoO3 template. Such developed δ-MnO2 hollow rods were systematically characterized and found to show impressive electrochemical properties with the maximum specific capacitance of 171.3 F g−1, satisfactory rate performance and exceptional cycle stability with capacitance retention as high as 90.5% even after repetitively charging/discharging for over 10,000 cycles. The remarkable supercapacitive behavior of porous δ-MnO2 hollow rods surpass those of many MnO2-based electrode materials, thus featuring the potential for development of advanced energy storage devices.