Synthesis of porous NiS nanoflake arrays by ion exchange reaction from NiO and their high performance supercapacitor properties

Abstract Metal sulfides have emerged as a new class of promising active material for supercapacitors. Porous NiS nanoflake arrays are successfully synthesized by a facile solution-based ion exchange reaction (IER) method based on preformed chemical bath deposition (CBD) derived NiO nanoflake arrays. NiS nanoflake arrays preserve the morphology of precursor-NiO nanoflake arrays and grow vertically to the substrates. As cathode of supercapacitors, NiS nanoflake arrays exhibit outstanding electrochemical performances with a high specific capacitance of 718 F g −1 at 2 A g −1 and good cycle performance and capacity retention (593 F g −1 after 3000 cycles at 2 A g −1 ).