ZIF-8-derived ZnO/C decorated hydroxyl-functionalized multi-walled carbon nanotubes as a new composite electrode for supercapacitor application
Kabir O. Otun, Morena S. Xaba, Shuang Zong, Xinying Liu, Diane Hildebrandt, Salah M. El‐Bahy, Mohammed T. Alotaibi, Zeinhom M. El‐Bahy
Abstract
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.