Hierarchical three-dimensional NiMoO4-anchored rGO/Ni foam as advanced electrode material with improved supercapacitor performance

Abstract

Designing a novel, efficient and cost-effective nanocomposite with the advantage of robust structure and outstanding conductivity is highly promising for the electrode materials of high-performance supercapacitors. Herein, we designed and synthesized a hierarchical structured NiMoO4@rGO/NF via a facile and scalable approach by growing NiMoO4 nanowires onto the skeleton of reduced graphene oxide (rGO)/Ni foam (NF). The as-made NiMoO4@rGO/NF exhibits a superior electrochemical behavior owing to the coupling effect of homogeneous NiMoO4 nanowires and high conductivity of rGO, and it exhibits a superb capacitance value of 1877 F g−1 at 1 A g−1 and shows a ultralong life span with over 98% capacitance retention after 4000 cycles at 5 A g−1 in 2 M KOH electrolyte. Moreover, an asymmetric device employing NiMoO4@rGO/NF composite and activated carbon is assembled with an aqueous electrolyte, and it displays a maximum energy density of 40 Wh kg−1 at a specific power 218.2 W kg−1. Interestingly, the asymmetric device can remain 111.2% of its initial value even after 8000 charge/discharge cycles. These results demonstrate that the NiMoO4@rGO/NF binder-free electrode provides greatly enhanced electrochemical performance and shows promising application as an anode for energy storage.