In-situ Growth of NiCo-MOF/MWCNT@NF Electrodes for High-Performance Hybrid Supercapacitors

Abstract Metal-organic frameworks (MOFs) are widely used as electrode materials due to their porous structure. However, their low conductivity often limits their further development. To overcome the issue, NiCo bimetallic organic framework (NiCo-MOF) and Multiwall carbon nanotube (MWCNT) were attached to Nickel foam (NF) surface without any binder by a simple one-step hydrothermal synthesis, resulting in electrodes with a regular linear layered structure. The structure promoted the electron/ion conduction and exposed more redox active sites, significantly improving electrochemical performance. The electrode prepared with Ni : Co = 1 : 2 and 2% MWCNT exhibited an areal specific capacitance of 5.94 C at 5 mA cm –2 and the capacity retention rate of 83.1% after 5000 cycles at 15 mA cm –2 . The areal-specific capacitance of the modified electrode material increased by nearly 7 times from 0.87 C to 5.94 C cm –2 . Hybrid supercapacitors (HSCs) consisting of the obtained electrodes and activated carbon (AC) had energy density up to 770 mW h cm –2 at a power density of 5.63 W cm –2 .