Oxygen and nitrogen co-doped porous carbon nanosheets derived from Perilla frutescens for high volumetric performance supercapacitors

Abstract Biomass-derived O/N-co-doped porous carbons have become the most competitive electrode materials for supercapacitors because of their renewability and sustainability. We herein present a simple approach to fabricate O/N-co-doped porous carbon nanosheets by the direct pyrolysis of Perilla frutescens (PF) leaves. Under optimum pyrolysis temperature (700 °C), the PF leaf-derived carbon nanosheets (PFC-700) having O, N contents of 18.76 at.% and 1.70 at.%, respectively, exhibit a hierarchical pore structure with a moderate BET surface area (655 m2 g−1) and a relatively low pore volume (0.44 cm3 g−1). Such O/N-co-doped porous carbon nanosheets display both high gravimetric capacitance (270 F g−1 at 0.5 A g−1) and high volumetric capacitance (287 F cm−3 at 0.5 A g−1). In addition, the PFC-700-based symmetric supercapacitor offers a high volumetric energy density (14.8 Wh L−1 at 490 W L−1) as well as a high stability (about 96.1% of capacitance retention after 10000 cycles at 2 A g−1).