Oriented growth of NiCo metal–organic framework nanosheets on electrode materials for ternary mixed metal oxide supercapacitors

Abstract

Metal–organic frameworks (MOFs) are porous structures that possess high specific surface areas, making them promising cathode materials for energy storage devices. However, solving the problems of random growth and easy aggregation of MOF nanosheets remains a challenge. In this study, hydrothermal and calcination methods were used to successfully create nickel cobalt molybdenum metal oxide (NCMO) nanoflowers, followed by the directional growth of NiCo–MOF on its surface. The oriented growth of NiCo–MOF nanosheets on NCMO nanospheres effectively prevented agglomeration, forming NCMO@NiCo–MOF with enhanced electrochemical sensitivity and a large quantity of active sites. When used as an electrode, NCMO@NiCo–MOF forms a large contact area with the electrolyte, demonstrating a high specific capacitance of 1724 F g−1 at a current density of 1 A g−1. Furthermore, at a power density of 824.8 W kg−1, an asymmetric supercapacitor constructed from NCMO@NiCo–MOF and activated carbon exhibited a high energy density of 44.5 Wh kg−1. This study presents a facile method for the assembly of MOF nanosheets for three-dimensional supercapacitors.