Self-supported NiMoO4@CoMoO4 core/sheath nanowires on conductive substrates for all-solid-state asymmetric supercapacitors

Elaborately developing metal oxide based core/sheath nanostructures are fascinating approaches to enhance the electrochemical properties of supercapacitors. Herein, we report the growth of hierarchal NiMoO4@CoMoO4 core/sheath nanowire arrays directly on the surface of Ni foam substrate via hydrothermal route and subsequent thermal treatment. Owing to the high utilization of electroactive materials and the efficient ion/electron transport pathways, the resulting binder-free NiMoO4@CoMoO4 electrode achieves a high areal capacitance up to 5.4 F cm(-2) at a current density of 2 mA cm(-2) and still maintains 3.1 F cm(-2) even at 40 mA cm(-2). In addition, the all-solid-state asymmetric supercapacitor (NiMoO4@CoMoO4//AC) with PVA/KOH gel electrolyte delivers a superior energy density of 49.3 Wh kg(-1) at 630 W kg(-1). The exceptional electrochemical performance demonstrates that the NiMoO4@CoMoO4 core/sheath nanowires are promising electroactive materials for advanced supercapacitors.