Mn-doped NiCoFeO4 based hierarchical Ni foam as binder-free electrode for all-solid-state asymmetric supercapacitor

Abstract

Herein, we demonstrate a facile hydrothermal method to directly grow Mn-doped NiCoFeO4 flower like hierarchical nanostructures on Ni-foam. The hierarchical morphology was confirmed by electron microscopic analysis and whereas formation of the ternary oxide was verified by X-ray diffraction analysis. Energy dispersive X-ray analysis confirmed the elemental composition. The Mn-doped NiCoFeO4 on Ni foam significantly outperformed the undoped NiCoFeO4 on Ni foam when tested as electrode material by three terminal electrochemical analysis as it exhibited specific capacitance of 500 mF/cm2 at a current density of 5 mA/cm2 which is five times that exhibited by the undoped NiCoFeO4 (99 mF/cm2) along with 83 % capacity retention after 7500 cycles at a high current density of 25 mA/cm2 highlighting the strong influence of Mn doping. Further, an all-solid state asymmetric supercapacitor (ASC) was fabricated using the hierarchical Mn-doped NiCoFeO4 on Ni-foam as anode and commercial activated carbon as cathode which exhibited power density of 2 mW/cm2 at energy density of 60 μWh/cm2 and was able to power a light emitting diode (LED) for 3 min. Thus, the novel Mn-doped hierarchical NiCoFeO4 on Ni-foam developed in this work shows great potential as a low-cost high-performance binder-free electrode for an all-solid-state asymmetric supercapacitor.