Nickel cobalt sulfide anchored in crumpled and porous graphene framework for electrochemical energy storage

Abstract

Energy storage is becoming highly important as renewable generation sources are added to the mix in electrical power generation and distribution systems. Supercapacitors and batteries could allow renewables to overcome intermittency difficulties by regulating the voltage, frequency, and phase angle of the power. Transition-metal oxide, hydroxide, and sulfide forms, carbonaceous materials, and conducting polymers can be used as electrodes for supercapacitors. Graphene is considered to be a promising material for supercapacitors because of its high surface area and theoretical gravimetric capacitance. However, aggregation of graphene sheets severely decreases the accessible surface area and theoretical gravimetric capacitance. Here we report a unique synthesis route of a hybrid nickel cobalt sulfide anchored in a crumpled and porous graphene framework to address the aforementioned problem. The hybrid sample, a nickel cobalt sulfide/crumpled-porous graphene framework, delivered higher specific capacitance and better electronic conductivity than the porous graphene framework when used as a supercapacitor electrode.