• Senthil, Karuppanan
• Kumar, Gunasekaran Rajendra
• Chinnadurai, Deviprasath
• Rajendiran, Rajmohan
• Selvaraj, Aravindha Raja

Abstract

ne dimensional manganese oxides with tunnel structures have attracted as an effective electrochemical energy storage material because of its efficient electrolyte/cation interfacial charge transports which enables improved pseudo capacitive performance. We have reported a simple one step hydrothermal technique to incorporate K+ ions to maintain the tunnel width of cryptomelane α-MnO2 nanowires during cycling performance. The effects of K+ ions on the electrochemical performance is studied by tuning the phases of α-KMnO2 nanowires to Mn3O4 through an intermediate phase of Mn2O3 by subsequent calcinations at various temperatures. K+ ions doped α-MnO2 nanowires exhibit a highest specific capacitance of 402 Fg-1 at a current density of 1 Ag-1 in 1 M Na2SO4 electrolyte solution compared to Mn2O3 and Mn3O4. The as synthesized α-KMnO2 nanowires have a wider tunnel widths and enriched O H radical species and hence the electrolyte cations (Na+) penetrate the tunnels very easily resulting the polarization enhanced intercalation pseudo capacitance. The symmetric α-KMnO2 nanowire supercapacitor device shows very high energy density (15.83 Wh kg−1), power density (128.35 W kg−1) and excellent cyclic stability with 88% retention of the initial capacitance after 3000 cycles.

Topics

• density
• impedance spectroscopy
• energy density
• phase
• current density
• interfacial
• Manganese