Porous-sheet-assembled Ni(OH)₂/NiS arrays with vertical in-plane edge structure for supercapacitors with high...

The use of hierarchical arrays of transition metal compounds directly grown on a current collector to fabricate a binder-free electrode is a promising strategy to achieve high-performance hybrid supercapacitors owing to their high surface area and low internal resistance. Engineering the microstructure of the hierarchical structure can further efficiently improve its capacitive performance. In this work, hierarchically structured Ni(OH)2/NiS/CC nanosheet arrays, with the vertical growth of secondary nanosheets on their surface, are directly fabricated on a carbon cloth via an NH4F-induced method. Due to adequate exposed-edge planes available on the surface, Ni(OH)2/NiS/CC exhibits remarkable electrocapacitive properties with a high specific capacity of 668 μA h cm-2 at 2 mA cm-2 in 3 M KOH medium, as well as excellent cycling performance (97% capacitance retention after 10 000 cycles). Besides, the Ni(OH)2/NiS/CC electrode also shows excellent performance as a flexible and lightweight electrode in a solid-state flexible supercapacitor.