Enhancing supercapattery performance and hydrogen evolution reaction through NiSrS/GQDs synergistic hetero-structure

ABS T R A C T Hybrid super capacitors are gaining popularity due to their enormous potential for energy-storing applications. A simple hydrothermal process was utilized for the synthesis of nickel strontium sulfide (NiSrS) and then graphene quantum dots (GQDs) were incorporated in different ratios to find out the optimized wt% ratio. An optimal combination of GQDs with NiSrS improved conductivity by producing higher active sites, which aids in modi-fying how the composite behaves electrochemically. The prepared NiSrS/GQDs-5% composite displayed an outstanding specific capacitance of 1881 C/g at 2.0 A/g. The developed aqueous-based anti-symmetric super-capattery device had an outstanding energy density of 44 Wh/kg at a power density of 1750 W/kg with remarkable capacitance retention of 98.3 % and columbic efficiency of 100 %. The NiSrS/NGQDs-5% demon-strated a low 87 mV during HER test. The exceptional electrochemical properties of GQDs-induced NiSrS pave the way for constructing highly effective electrode materials, making them ideal for supercapacitor applications.