A hierarchical porous aerogel nanocomposite of graphene/NiCo2S4 as an active electrode material for supercapacitors

Abstract

A three-dimensional reduced graphene oxide/nickel-cobalt sulfide (RGO/NiCo2S4) aerogel was fabricated by an efficient and facile one-step hydrothermal approach. The NiCo2S4 needle-like structure consisted of many small nanoparticles well attached to the surface of the RGO sheet. The prepared aerogel had high porosity and conductivity. As an active electrode material for supercapacitors, the RGO/NiCo2S4 aerogel exhibited a large capacitance of 813 F g−1 at 1.5 A g−1. Besides, the asymmetric supercapacitor (RGO/NiCo2S4 aerogel//RGO) showed a Cs of 45.3 F g−1 at 1.0 A g−1 and a suitable remaining capacitance of over 84.3 % after 2000 cycles. The asymmetric supercapacitor had a high energy density of 40.3 Wh kg−1 at 375.0 W kg−1 and a power density of 26.2 kW kg−1 at 3.7 kWh kg−1, which suggests this device has great potential applications in energy storage.

Keywords

• Graphene
• Nickel-cobalt sulfides
• Hydrothermal method
• Aerogel nanocomposites
• Supercapacitors