Enhancing supercapacitor performance through graphene flame synthesis on nickel current collectors and active carbon material from plant biomass

Abstract

This study introduces a novel approach utilizing flame-synthesized few-layer graphene on a metal current collector for energy storage devices. The graphene was synthesized through a scalable, one-step method involving a flame generated by pre-mixed propane/oxygen/argon gases. To ensure purity and eliminate undesired amorphous structures, ultrasonication was employed. The method successfully produced 5 to 10 layers of graphene on a nickel substrate with rapid growth rates (30–60 s) facilitated by a steady supply of precursors at a stable temperature. The resulting current collector was utilized in the assembly of a supercapacitor, where activated carbon derived from barley straw served as the active electrode material. The cycling stability test reveals that all electrodes maintain approximately 98 % of their initial specific capacitance over 5000 charge-discharge cycles, except for the Ni/Flame-based graphene current collector, which experiences a substantial decrease in capacitance. This study presents a scalable and straightforward concept for incorporating thin layers of graphene onto a metal current collector to enhance the electrochemical characteristics of the electrode. The continuous processing capability and high growth rate of graphene contribute to the method's effectiveness. The study demonstrates the potential of flame-synthesized few-layer graphene for improving the electrochemical properties of supercapacitor electrodes, and its suitability for large-scale production, making it a promising avenue for future energy storage advancements.