▎ 摘　　要

ZnCo2O4-rGO composite with intertwined sheets grown onto nickel foam substrate is prepared through a facile hydrothermal deposition and followed thermal annealing treatment, which can be directly employed as binder free electrode of supercapacitor. The hierarchically porous texture of ZnCo2O4-rGO composite with high specific surface area and efficient ions diffusion channels ensures sufficient faradic reaction of ZnCo2O4 component, therefore enables an ultrahigh electrode specific capacitance (C-s) of 3222 F g(-1) at 1 A g(-1) in alkali electrolyte, and the C-s still retains to be 860 F g(-1) at 20 A g(-1). When used as positive electrode of full cell, the ZnCo2O4-rGO//activated carbon (AC) asymmetric supercapacitor can offer a maximum device specific capacitance (C-cell) of 139 F g(-1) at 0.5 A g(-1) and therefore an energy density (E-cell) of 49.1 Wh kg(-1) at power density (P-cell) of 400Wkg(-1). Even at high P-cell of 7625 Wkg(-1), the E-cell of the asymmetric device can still retain to be 18.8 Wh kg(-1). More significantly, the asymmetric supercapacitor demonstrates only 6% C-cell fade subjected to 5000 successive charge-discharge cycles. The balanced E-cell, P-cell delivery abilities and high cycleability highlight the potential of the faradic ZnCo2O4-rGO composite in high performance and long lifetime energy storage devices. (C) 2018 Elsevier B.V. All rights reserved.