LAUSR

Metal-organic frameworks (MOFs) have been considered as a class of promising electrode materials for supercapacitors owing to their large surface area, rich porosity and variable redox sites, however, direct application of pristine MOFs in energy storage has been largely hindered by their poor electrical conductivity and stability issues. Herein, we demonstrate a facile two-step approach to address the controlled growth of Ni-MOF arrays on the surface of NiCo2O4 nanowires by modulating the formation reaction of MOFs. By taking advantage of the intriguing merits from the NiCo2O4 core and Ni-MOF shell as well as their synergistic effects, the optimized NiCo2O4@Ni-MOF hybrid electrode exhibits boosted electrochemical performance, in terms of high specific capacity (208.8 mAh/g at 2 mA/cm2) and good rate capability. Moreover, the assembled flexible solid-state HSC device based on the optimized NiCo2O4@Ni-MOF and activated carbon (AC) as the cathode and anode, achieves a maximum energy density of 32.6 Wh/kg at a power density of 348.9 W/kg without sacrificing its excellent cycling stability (nearly 100% retention over 6000 cycles at 8 mA/cm2) and mechanical stability, outperforming most recently reported MOF-based HSC devices in aqueous electrolyte. Our work demonstrates the possibility of exploiting novel MOF-based hybrid arrays as battery-type electrodes with enhanced electrochemical properties, which exhibits great potential in flexible energy storage devices.