Construction of zeolitic imidazolate frameworks-derived NixCO3-xO4/reduced graphene oxides/Ni foam for enhanced energy storage performance

Direct assembling 2D zeolitic imidazolate frameworks-derived (ZIFs)-derived Ni-Co oxide on Ni foam (NixCo3-xO4/Ni foam) is a very attractive way to obtain high performance for electrochemical energy storage device. In this work, the highly optimized NixCo3-xO4/Ni foam was prepared via facile coprecipitation, ion-exchange method and subsequently composited with rGO, acting as binder-less electrode for high properties hybrid supercapacitors. As electrode materials, the pure Co3O4/Ni foam shows 94.40 C g(-1) (209.78 F g(-1)) at 1 A g(-1), while the highly optimized NixCo3-xO4/Ni foam exhibits a high capacity of 870.3 C g(-1) (1934F g(-1)) at 1 A g(-1). Compared with NixCo3-xO4/Ni foam, the reduced graphene oxides (rGO) modified NixCo3-xO4/Ni foam electrodes possess a porous conductive structure, displaying more superior capacity of 1440.99 C g(-1) (3202.22F g(-1)) at 1 A g(-1) and a higher cycling stability of 76.10% retention value after 1000 cycles. Subsequently, the NixCo3-xO4/rGO/Ni foam electrodes were assembled as a hybrid supercapacitor, exhibiting a maximum energy density of 36.31 Wh kg(-1), a maximum power density of 8000 W kg(-1) and a good cycling stability of 76.29% retention value after 3000 cycles. The NixCo3-xO4/rGO/Ni foam also could light the blue LED device. Thereby, it is proved that NixCo3-xO4/rGO/Ni foam is a promising materials for hybrid supercapacitors. (C) 2019 Elsevier Inc. All rights reserved.