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 degrees C, porous structure formed with a large specific surface area of 784-1836 m(2)g(-1) and pore volume of 0.46-1.10 cm(3)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 Fg(-1) at 0.5 Ag-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 Ag-1. The outstanding electrochemical performance of N-doped porous carbon makes it a potential candidate for electrical double-layer capacitor electrode material.