Green activation of sustainable resources to synthesize nitrogen-doped oxygen-riched porous carbon nanosheets towards high-performance supercapacitor

Engineering 2D porous carbon can considerably boost the energy storage performances of supercapacitors via empowering rapid ion transport and charge transfer kinetics. Therein, manufacturing porous carbon nanosheets with high surface area by virtue of sustainable and cost-efficient synthesis strategy has attracted enormous interests. Herein, 2D nitrogen-doped oxygen-riched carbon nanosheets (NOCNs) with hierarchical pores were facilely synthesized via green activation processes. Combining the sustainable resources such as citric acid and urea with magnesium carbonate basic, it well achieves the nitrogen-doping and in-situ MgO templates embedding within carbon matrix. The optimal NOCN900 sample presents a unique 2D sheet-like morphology together with hierarchical pores and high specific surface area (1804.2 m2 g−1). Benefiting its microstructural advantages, the NOCN900 exhibits a high specific capacitance of 232F g−1 at 0.5 A g−1 and superior rate capability in alkaline electrolyte. In addition, the maximum energy density of the NOCN900-based symmetrical supercapacitor reaches 17 Wh kg−1 at the power density of 450 W kg−1, demonstrating promising application prospects. The strategy advocated here for synthesizing 2D carbon nanosheets offers new insights into exploring sustainable and cost-efficient energy storage materials.