From barley straw biomass to N/S co-doped as electrode material for high-performance supercapacitor applications

An innovative and cost-efficient methodology is proposed for developing porous carbon materials from barley straw biomass waste using thiourea as dopant and FeCl3 as activator. By varying precursor ratio and activation, porous carbon frameworks (BCF-Ts) with tailored porosity and N/S-doping were synthesized. BCF-Ts showed remarkable pore size distribution and high surface area responsible for enhanced electrochemical performance by enabling efficient ion transmission. The optimized N/S-doped activated carbon (BCF-T) exhibited high specific surface area of 938.7 m2 g-1. As supercapacitor electrode, BCF-T displayed exceptional performance including high specific capacitance of 496 F g-1, power density of 500.95 Wkg-1, and energy density of 42.02 Whkg- 1 in KOH electrolyte. Moreover, BCF-T showed impressive cyclic stability, retaining 90.13 % capacitance after 2000 cycles. The tailored porosity, heteroatom doping, large surface area, and proper graphitization of BCFT facilitated rapid ion diffusion, sufficient charge storage, and pseudocapacitance. This work provides valuable guidance on synthesizing high-performance porous carbon materials from biomass waste for supercapacitor applications.