Muhiuddin, M.Devi, N.A.Bharadishettar, N.Meti, S.Siddique, A.B.Satyanarayan, M.N.Udaya, B.K.Akhtar, W.Rahman, M.R.2026-02-042024Diamond and Related Materials, 2024, 146, , pp. -9259635https://doi.org/10.1016/j.diamond.2024.111232https://idr.nitk.ac.in/handle/123456789/21075The current invention pertains to the expeditious simple synthesis of electrode materials that improve the storage capacity of supercapacitors (SCs). Sulfur and nitrogen co-doped graphene quantum dots (SN-GQDs) are synthesized using a microwave-assisted hydrothermal (MAH) process at low pressure and with a short reaction time. The utilization of SN-GQDs in conjunction with Polyaniline (PANI) has the potential to enhance the supercapacitor's energy and power density, owing to their notable specific capacitance. Implementing SN-GQDs material as an SCs electrode, exhibiting an outstanding specific capacitance of 1040 F/g at an applied current density of 0.5 A g−1. Furthermore, a composite of SN-GQDs/PANI is synthesized and the electrochemical performance is compared with the as-synthesized PANI. The symmetrical SCs are fabricated using SN-GQDs/PANI composite, and PANI. At a current density of 0.5 A g−1 SN-GQDs/PANI composite-based SC displays a superior energy density of 44.25 Wh/kg at a power density of 1.227 kW/kg. This is high in comparison to PANI-based SC which shows an energy density of 18.71 Wh/kg at 0.8 kW/kg power density at the same current density. The SC created using SN-GQDs/PANI composite exhibits superior properties and is a promising material for SC applications. © 2024 Elsevier B.V.CapacitanceCurrent densityElectrodesGrapheneHydrothermal synthesisNanocrystalsNitrogenSemiconductor quantum dotsSulfurCo-dopedEnergy densityGraphene quantum dotMicrowave-assisted hydrothermalPower densitiesSpecific capacitanceSymmetric supercapacitorSymmetricsSynthesisedSupercapacitor