Hierarchically porous Nb-δMnO2@CC as anode material for exceptional high performance aqueous asymmetric hybrid super capacitor

Abstract

Super-capacitors are being widely investigated as sustainable power supply for next generation portable electronics. The synergy of high charge storage capability and enhanced mechanical properties are crucial for realization of hybrid aqueous asymmetric super capacitors. Herein, we report the fabrication of hierarchal porous Nb doped MnO₂ on carbon cloth (CC) as anode material through one pot hydrothermal process. The smaller atomic and ionic radius of Nb facilitate the fast intercalation and de-intercalation, thereby enhancing the rate capability and charge storage whereas the carbon cloth endows the nanocomposite the superior mechanical strength, enhanced conductivity and a path to the charge transport. The hierarchical porous structure of Nb-δMnO₂@CC possess multitude of active sites for charge/ion transport and enlarged surface area which assures its superior electrochemical performance. Operating within a potential range of 0–2 V, the as designed anode material Nb-δMnO₂@CC shows excellent reversible capacitance of 633.6 F/g. An asymmetric hybrid super-capacitor was designed Nb-δMnO₂@CC // AC, employing Nb-δMnO₂@CC as anode and activated carbon as counter electrode, delivers a remarkable specific capacitance of 255.1 F/g, an improved energy density of 141.7 Wh/Kg and Power density of 999.8 W/Kg. The findings of this research will enable the creation of high-performance aqueous asymmetric hybrid super-capacitors, offering improved capacitance, energy density, and power density.