Hierarchical Multicomponent Electrode with Interlaced Ni(OH)₂ Nanoflakes Wrapped Zinc Cobalt Sulfide Nanotube Arrays for Sustainable High‐Performance Supercapacitors

Abstract

Abstract High energy density, fast recharging ability, and sustained cycle life are the primary requisite of supercapacitors (SCs); these necessities can be fulfilled by engineering a smart current collector with hierarchical combination of different active materials. This study reports a multicomponent design of hierarchical zinc cobalt sulfide (ZCS) hollow nanotube arrays wrapped with interlaced ultrathin Ni(OH) 2 nanoflakes for high‐performance electrodes. The ZCS exhibits a unique pentagonal cross‐section and a rough surface that facilitates the deposition of Ni(OH) 2 nanoflakes with a thickness of 7.5 nm. The ZCS/Ni(OH) 2 hierarchical electrode exhibits a high specific capacitance of 2156 F g −1 and excellent cyclic stability with 94% retention over 3000 cycles. This is attributed to enhanced redox reactions, the direct growth of arrays on 3D porous foam acting as a “superhighway” for electron transport, and the increased availability of electrochemical active sites provided by the ultrathin Ni(OH) 2 flakes that also sustain the stability of the electrode by sacrificing themselves during long charge/discharge cycles. Symmetric SCs are assembled to achieve high energy density of 74.93 W h kg −1 and exhibit superior cyclic stability of 78% retention with 81% coulombic efficiency over 10 000 cycles.