ZIF-8-derived ZnO/C decorated hydroxyl-functionalized multi-walled carbon nanotubes as a new composite electrode for supercapacitor application

Due to the poor conductivity of metal-organic frameworks (MOFs), it is challenging to directly employ MOFs as electrode materials for supercapacitors. Herein, hydroxyl-functionalized multi-walled carbon nanotube (f-MWCNT) was used to decorate ZnO/C obtained from the prior calcination of pristine zeolitic imidazolate framework-8 (ZIF-8) and applied as electrode material for supercapacitor application. The resulting ZnO/[email protected] electrode exhibits excellent storage performance, as confirmed by the specific capacitance of 650 F/g at 1 A/g and a superior energy/power density compared to the single electrode. Additionally, the composite electrode displayed remarkable cycling stability of 70% after 5000 cycles and retained 75% of its initial capacitance at 10 A/g, demonstrating good rate cyclability. The exceptional performance of ZnO/[email protected] was attributed to the synergistic effects offered by f-MWCNT which improved its electrical conductivity and ZnO/C that provided sufficient redox-active sites and structural stability. This work may promote the design of advanced MOF-based nanocomposites for energy storage application.