MnO2 Nanoflowers Decorated on ZIF‐8‐ZnO with Ni Foam Supportfor High‐Performance Supercapacitors

Abstract

AbstractIn this study, ZIF‐8 (Zn(MeIn)2, MeIn=2‐methylimidazole) was synthesized directly on Ni foam with the use of polydopamine (PDA). By following a hydrothermal process, MnO2 nanoflowers were decorated on the hybrid material of ZIF‐8/ZnO, as derived from ZIF‐8 via pyrolysis at 500 °C under nitrogen flow. The produced binder‐free electrode (NF/ZIF‐8‐ZnO/MnO2) demonstrated an excellent electrochemical performance for supercapacitors, including a specific capacitance of 2005 F g−1 at 2 A g−1 and a fairly high cycling stability (90.74% retention after 4000 cycles). Furthermore, a NF/ZIF‐8‐ZnO/MnO2//activated carbon (AC) asymmetric supercapacitor showed an energy density of 70.57 Wh kg−1 given a power density of 112.45 kW kg−1. These results demonstrate that NF/ZIF‐8‐ZnO/MnO2 is a promising candidate for supercapacitors due to the synergistic contribution of ZIF‐8, ZnO and MnO2.