Hierarchical Columnar Cactus-like Co-MOF@NiCo-LDH Core–Shell Nanowrinkled Pillar Arrays for Supercapacitors with Ultrahigh Areal Capacitance

Abstract

The design of metal–organic framework/layered double hydroxide (MOF/LDH) heterogeneous hybrids is crucial to the enhancement of areal capacitance for supercapacitor electrodes. Herein, the NiCo-LDH nanowrinkles are evenly epitaxially grown on the surface of self-supported Co-MOF nanoneedles to form aligned nanopillar arrays by a facile electrodeposition. Thanks to the high porosity of the Co-MOF, excellent redox activity of NiCo-LDH, and interfacial synergy of the core–shell multicomponent heterostructure, the Co-MOF@NiCo-LDH composite has an extraordinary areal capacitance (44.1 F cm–2 at 5 mA cm–2), which is 7.6 and 2.6 times higher than that of the bare NiCo-LDH and Co-MOF, respectively. Furthermore, the constructed asymmetric supercapacitor with activated carbon demonstrates a satisfactory energy density of 0.89 mWh cm–2 at the power density of 7.5 mW cm–2 and superior cycling stability (97.6% capacitance retention after 10,000 cycles).