Highly exposed nickel cobalt sulfide–rGO nanoporous structures: an advanced energy-storage electrode material

Abstract

Uncontrollable diffusion and the associated decrease in rate have hampered the development of robust nanostructured porous metal sulfides to date. Herein, we report a robust and porous NiCo₂S₄ nanostructure grown on graphene oxide using a facile synthesis method. The obtained ultrathin NiCo₂S₄ nanosheets contain a broad range of nanopores and their graphene backbone enhances the surface area as well as conductivity of the entire matrix. The advantages of the synthetic approach were evaluated by investigating the supercapacitor efficiency of the obtained nanomaterial, where the highly porous and exposed nanocomposite delivered the high capacitance of 1527 F g⁻¹ at 10 mV s⁻¹ in 1.0 M KOH. The high capacitive nanomaterial electrode coupled with graphene–single wall carbon nanohorn heterostructures provides a maximum energy of 60.9 W h kg⁻¹ at 1.4 kW kg⁻¹ power density, which reveals the merits of the synthetic approach and its application in progressive electrochemical energy storage/conversion devices.