Preparation and capacitive properties of nitrogen-doped graphene aerogels compatible with ionic liquid electrolyte

Abstract

<p indent="0mm">Nitrogen-doped graphene aerogels for high performance supercapacitors were synthesized using guanidine phosphate, guanidine carbonate and guanidine hydrochloride as the nitrogen source by a facile and cost-effective hydrothermal method. X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy characterizations and nitrogen adsorption/desorption analysis indicate that these nitrogen doped graphene aerogels have poorly ordering and hierarchical porous structures. Especially, the nitrogen-doped graphene aerogel (HRGA) prepared using guanidine hydrochloride as the nitrogen source possesses a richer nitrogen content (9.7 at%), higher conductivity <sc>(11.2 S cm⁻¹),</sc> and larger specific surface area <sc>(257.6 m² g⁻¹).</sc> Thus HRGA delivers a large specific capacitance of <sc>176 F g⁻¹</sc> at a current density of <sc>1 A g⁻¹</sc> and an energy density of 70 Wh kg⁻¹ at a power density of <sc>0.875 kW kg⁻¹.</sc> The nitrogen-doped graphene aerogels with enhanced electrochemical performance provide a huge application potential in the energy storage field.