Template-free preparation of nitrogen-doped activated carbon with porous architecture for high-performance supercapacitors

Nitrogen-doped porous activated carbon was prepared via a hydrothermal process using glucosamine as both carbon and nitrogen source without any template. After activated by KOH at 600–800 °C, porous structure formed with a large specific surface area of 784–1836 m2 g−1 and pore volume of 0.46–1.10 cm3 g−1. The activated N-doped (1.71–2.81 at%) carbon structure with interconnected micro and mesoporous structures exhibits excellent electrochemical performance as supercapacitor electrode, demonstrating a high specific capacitance of 244–313 F g−1 at 0.5 A g−1 and a good cyclic stability with 92.7–93.9% capacitance retention over 5000 cycles in 6 M KOH aqueous solution. The all-solid-state symmetric supercapacitor using the N-doped porous carbon electrodes and PVA/KOH gel as electrolyte reveals an energy density of 7.2 W h kg−1 at a power density of 250 W kg−1 and outstanding stability of 93% capacitance retention after 5000 cycles at 2 A g−1. The outstanding electrochemical performance of N-doped porous carbon makes it a potential candidate for electrical double-layer capacitor electrode material.