Design and fabrication of free-standing Ni3S2/NiV-LDH nanosheets arrays on reduced graphene oxide/Ni foam as a novel electrode for asymmetric supercapacitor

Abstract

Composite electrodes that possess both appropriate integration and reasonable structures are needed to provide eminent electrochemical performance in energy storage devices. At this work, an innovative electrode material with a composite structure of Ni3S2/NiV-LDH nanosheets fixed on the reduced graphene oxide/Ni Foam (rGO/NF) was fabricated by a convenient two-step hydrothermal process. The intriguing compositional/componental advantages significantly facilitate the efficient penetration of the electrolytes and increase active sites of redox reactions in energy storage application. The Ni3S2/NiV-LDH/rGO/NF electrode reaches a standout specific capacitance of 3004.3 F g−1 at a current density of 1 A g−1 and a superb cycle stability with 92.2% capacitance retention after 5000 cycles. Furthermore, an asymmetric supercapacitor (Ni3S2/NiV-LDH/rGO/NF//AC) was also assembled, achieving a high energy density of 59.4 Wh kg−1 at 852.3 W kg−1 and favourable cycle life, where 98.3% of the capacitance was retained after 8000 cycles. These consequences show that Ni3S2/NiV-LDH/rGO/NF composite is a potential electrode material in the future.