Decorating MnO₂ nanosheets on MOF-derived Co₃O₄ as a battery-type electrode for hybrid supercapacitors

Metal-organic framework-derived materials are now considered potential next-generation electrode materials for supercapacitors. In this present investigation, Co₃O₄@MnO₂ nanosheets are synthesized using ZIF-67, which is used as a sacrificial template through a facile hydrothermal method. The unique vertically grown nanosheets provide an effective pathway for rapidly transporting electrons and ions. As a result, the ZIF-67 derived Co₃O₄@MnO₂-3 electrode material shows a high specific capacitance of 768 C g^-1 at 1 A g^-1 current density with outstanding cycling stability (86% retention after 5000 cycles) and the porous structure of the material has a good BET surface area of 160.8 m² g^-1. As a hybrid supercapacitor, Co₃O₄@MnO₂-3//activated carbon exhibits a high specific capacitance (82.9 C g^-1) and long cycle life (85.5% retention after 5000 cycles). Moreover, a high energy density of 60.17 W h kg^-1 and power density of 2674.37 W kg^-1 has been achieved. This attractive performance reveals that Co₃O₄@MnO₂ nanosheets could find potential applications as an electrode material for high-performance hybrid supercapacitors.