In Situ Construction of ZIF-67-Derived Hybrid Tricobalt Tetraoxide@Carbon for Supercapacitor

The Co₃O₄ electrode is a very promising material owing to its ultrahigh capacitance. Nevertheless, the electrochemical performance of Co₃O₄-based supercapacitors is practically confined by the limited active sites and poor conductivity of Co₃O₄. Herein, we provide a facile synthetic strategy of tightly anchoring Co₃O₄ nanosheets to a carbon fiber conductive cloth (Co₃O₄@C) using the zeolitic imidazolate framework-67 (ZIF-67) sacrificial template via in situ impregnation and the pyrolysis method. Benefiting from the enhancement of conductivity and the increase in active sites, the binder-free porous Co₃O₄@C supercapacitor electrodes possess typical pseudocapacitance characteristics, with an acceptable specific capacitance of ~251 F/g at 1 A/g and long-term cycling stability (90% after cycling 5000 times at 3 A/g). Moreover, the asymmetric and flexible supercapacitor composed of Co₃O₄@C and activated carbon is further assembled, and it can drive the red LED for 6 min.