Ni Foam-Supported Carbon-Sheathed NiMoO₄ Nanowires as Integrated Electrode for High-Performance Hybrid Supercapacitors

Abstract

Rational design of hierarchical nanostructure arrays as integrated electrodes with the capability of storing energy has been studied extensively. However, a low electronic/ionic transport rate and structural instability hampered their practical application. In this study, we have fabricated carbon-sheathed NiMoO4 nanowires standing on nickel foam (NF) and employed as a free-standing electrode for supercapacitor. The unique structure revealed remarkable electrochemical behavior including a high areal capacitance, ∼70% capacitance retention at 100 mA cm–2, and an stability during cycling (86% retention after 50,000 cycles). In addition, an NF@NiMoO4@C//activated carbon hybrid supercapacitor presents 201.3 F g–1 of specific capacitance along with an 72.4 W h kg–1 of energy density. The carbon sheath, which prevents the structural pulverization of NiMoO4 and provides another conductive path together with Ni foam, is responsible for the superior electrochemical performances. Our work demonstrates an improved step toward rational design of high-performance integrated electrodes for a supercapacitor with a new vision for theoretical and practical applications.