Fe-MnO2 core-shell heterostructure for high-performance aqueous asymmetrical supercapacitor

Abstract Core-shell heterostructure of birnessite type Fe-doped manganese oxides binder and conductive agent-free electrode is prepared on carbon cloth via a hydrothermal method, which improves the conductivity and capacitance for the high-performance aqueous asymmetrical supercapacitor. The Fe-MnO2 electrode has a specific capacitance of about 350 F g−1 at the current density of 1 A g−1. We further drafted a high potency aqueous asymmetric supercapacitor (Fe-MnO2//AC) with Fe-MnO2 as the positive electrode at the extendable working potential window of 0–2.0 V, which manifests an outstanding energy density of 40 Wh kg−1 with a maximum power density of 3956 W kg−1 and an excellent cycling performance with capacitance retention of 88.8% at the current density of 10 A g−1 after 6000 cycles.