Constructionof Hierarchical NiCo 2 O 4 @Ni-MOF Hybrid Arrayson Carbon Cloth as Superior Battery-TypeElectrodes for Flexible Solid-State Hybrid Supercapacitors

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. In this work, 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 mA h/g at 2 mA/cm2) and good rate capability. In addition, the assembled flexible solid-state HSC device based on the optimized NiCo2O4@Ni-MOF and activated carbon as the cathode and anode achieves a maximum energy density of 32.6 W h...