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

Abstract

Rational\ndesign of hierarchical nanostructure arrays as integrated\nelectrodes with the capability of storing energy has been studied\nextensively. However, a low electronic/ionic transport rate and structural\ninstability hampered their practical application. In this study, we\nhave fabricated carbon-sheathed NiMoO₄ nanowires standing\non nickel foam (NF) and employed as a free-standing electrode for\nsupercapacitor. The unique structure revealed remarkable electrochemical\nbehavior including a high areal capacitance, ∼70% capacitance\nretention at 100 mA cm^–2, and an stability during\ncycling (86% retention after 50,000 cycles). In addition, an NF@NiMoO₄@C//activated carbon hybrid supercapacitor presents 201.3\nF g^–1 of specific capacitance along with an 72.4\nW h kg^–1 of energy density. The carbon sheath, which\nprevents the structural pulverization of NiMoO₄ and provides\nanother conductive path together with Ni foam, is responsible for\nthe superior electrochemical performances. Our work demonstrates an\nimproved step toward rational design of high-performance integrated\nelectrodes for a supercapacitor with a new vision for theoretical\nand practical applications.