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 (Ni x Co 3−x O 4 /Ni foam) is a very attractive way to obtain high performance for electrochemical energy storage device. In this work, the highly optimized Ni x Co 3−x O 4 /Ni foam was prepared via facile co-precipitation, ion-exchange method and subsequently composited with rGO , acting as binder-less electrode for high properties hybrid supercapacitors . As electrode materials , the pure Co 3 O 4 /Ni foam shows 94.40 C g −1 (209.78 F g −1 ) at 1 A g −1 , while the highly optimized Ni x Co 3−x O 4 /Ni foam exhibits a high capacity of 870.3 C g −1 (1934F g −1 ) at 1 A g −1 . Compared with Ni x Co 3−x O 4 /Ni foam, the reduced graphene oxides (rGO) modified Ni x Co 3−x O 4 /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 Ni x Co 3−x O 4 /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 Ni x Co 3−x O 4 /rGO/Ni foam also could light the blue LED device. Thereby, it is proved that Ni x Co 3−x O 4 /rGO/Ni foam is a promising materials for hybrid supercapacitors.