Phosphorus and nitrogen co-doped reduced graphene oxide as superior electrode nanomaterials for supercapacitors

Abstract

Phosphorus/nitrogen co-doped reduced graphene oxide (PN-rGO) materials have been prepared by one-step pyrolysis of the functionalized GO (FGO) with hexachlorocyclotriphosphazene and p-phenylenediamine. The resulting PN-rGO shows a porous structure with a transparent and wrinkled thin film morphology. Compared with undoped rGO, the electrochemical measurements of PN-rGO reveal enhanced capacitive properties, including a high specific capacitance of 292 F g⁻¹ at 0.5 A g⁻¹, remarkable rate capability, and excellent cycling stability (after 10 000 cycles, 97% capacitance is maintained). Moreover, the assembled symmetric supercapacitor using PN-rGO shows a relatively high energy density of 8.2 W h kg⁻¹ at a power density of 570 W kg⁻¹ in KOH electrolyte. The outstanding performance of this material as a supercapacitor electrode may be attributed to the pseudocapacitive effect of P/N co-doping in reduced graphene nanosheets, as well as its exceptional porous structure.