High-performance α-MnO2 nanowire electrode for supercapacitors

Nanowired alpha-MnO2 material supported on carbon fiber paper (alpha-MnO2/CFP) is synthesized using a facile hydrothermal method for supercapacitor electrode. The alpha-MnO2/CFP material is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and BET for its composition, structure/morphology, and BET surface area. The electrochemical properties of the alpha-MnO2/CFP electrode are studied by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) in 1 M Na2SO4 solution. The porous alpha-MnO2/CFP material electrode shows a high specific capacitance of 251 F g(-1) at the current density of 1 A g(-1), and also exhibits a good rate capability and an excellent cycling stability. It is testified that even after 3000 cycles, the capacitance retention of the porous alpha-MnO2/CFP material electrode can still maintain over 98.9% of the capacitance at the high current density of 4 A g(-1), demonstrating its excellent cycling stability. The high electrochemical performance of the porous alpha-MnO2/CFP material nanowire electrode may be attributed to the 2 x 2 tunnel structure, high active surface area, and high porosity of the of alpha-MnO2 material. (C) 2014 Published by Elsevier Ltd.