Hierarchical CuCo2O4@CoS-Cu/Co-MOF core-shell nanoflower derived from copper/cobalt bimetallic metal–organic frameworks for supercapacitors

Abstract

Rational design of composite materials with unique core-shell nanoflower structures is an important strategy for improving the electrochemical properties of supercapacitors such as capacitance and cycle stability. Herein, a two-step electrodeposition technique is used to orderly synthesize CuCo2O4 and CoS on Ni foam coated with Cu/Co bimetal metal organic framework (Cu/Co-MOF) to fabricate a hierarchical core-shell nanoflower material (CuCo2O4@CoS-Cu/Co-MOF). This unique structure can increase the electrochemically active site of the composite, promoting the Faradaic redox reaction and enhancing its electrochemical properties. CuCo2O4@CoS-Cu/Co-MOF shows a prominent specific capacitance of 3150 F g−1 at 1 A g−1, marvelous rate performance of 81.82% (2577.3 F g−1 at 30 A g−1) and long cycle life (maintaining 96.74% after 10,000 cycles). What is more, the assembled CuCo2O4@CoS-Cu/Co-MOF//CNTs device has an energy density of 73.19 Wh kg−1 when the power density is 849.94 W kg−1. It has unexpected application prospects.