Fabrication of nitrogen and sulfur co-doped graphene nanoribbons with porous architecture for high-performance supercapacitors

•A novel approach for the synthesis of unique porous NS-GNR by thermal annealing method has been established.•The highly synergistic NS-GNR is proposed here for the first time as an electrode for supercapacitors.•NS-GNR exhibited an excellent specific capacitance of 442 F g−1 at 0.5 A g−1 and extraordinary rate capability.•The assembled NS-GNR//NS-GNR device showed high energy density of ∼23.85 Wh kg−1 at a power density of ∼448 W kg−1.

Heteroatom co-doped carbon-based materials have been demonstrated to be an effective way to realize their new functions in electrode materials for energy storage devices. Herein, a novel strategy for synthesis of highly porous nitrogen-sulfur co-doped graphene nanoribbons (NS-GNRs) with enhanced active sites was developed. The highly porous NS-GNR channels provide efficient ion transport path for electrolyte ions, which enhances the overall conductivity and stability of the electrode materials by energising storage sites. The TEM and STEM-EDS analysis revealed that the NS-GNR materials exhibit uniform distribution of N and S heteroatoms into GNRs matrices. The NS-GNR electrode materials exhibited a high specific capacitance of 442 F g−1 at 0.5 A g−1, excellent rate capability and cycling performance with ∼98.6 % retention of the initial capacitance after 10,000 cycles. Most importantly, the fabricated symmetric supercapacitor device with a wide operating voltage window of ∼1.8 V yield an excellent energy density of ∼23.85 Wh kg−1, high power density of ∼8753 W kg−1 and superior cycle life (97.9% capacitance retention after 10,000 cycles). Thus, these results exhibit a novel metal-free and low-cost design of electrode materials for high-performance energy storage devices.

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