Nitrogen and sulfur co-doped graphene-like carbon sheets derived from coir pith bio-waste for symmetric supercapacitor applications

An efficient synthesis of nitrogen and sulfur co-doped graphene-like carbon sheets from coir pith bio-waste through the mechanical activation method is reported in this study. The structural characterization reveals the presence of a graphene-like carbon sheet, which is uniformly doped with nitrogen and sulfur atoms in a carbon network. The nitrogen and sulfur co-doped graphene-like carbon sheets (NSG) has amorphous nature with a defective porous carbon structure and it depicts the maximum specific capacitance of 247.1Fg(-1) at 0.2Ag(-1) and a capacitance retention of 75.2% at 10Ag(-1). The synthesized NSG-10 registered a maximum energy density of 33.6Whkg(-1) at 0.2Ag(-1) and shows the maximum power density of 4220.0Wkg(-1) at 10.0Ag(-1). Furthermore, a symmetric supercapacitor (SSC) device shows the device capacitance of 33.7Fg(-1) at 0.2Ag(-1) when operated at 1.0V. The SSC device gives a capacitance retention of 82.0% at 10Ag(-1) and reveals an excellent stability with no losses in capacitance with 100% columbic efficiency over 10,000 cycles. The results suggest that the proposed methodology is a simple and unique way to synthesize heteroatoms-doped graphene-like carbon sheets from biomass materials for a supercapacitor. [GRAPHICS] .