Facilely prepared, N, O-codoped nanosheet derived from pre-functionalized polymer as supercapacitor electrodes

Nitrogen and oxygen codoped carbon nanosheets derived from pre-functionalized polymer were prepared using a facile direct pyrolysis method. The carbon microstructures are tunable with micro- and mesopore size distribution and a large specific surface area (1628.9–2146.1 m² g⁻¹). Furthermore, a significant morphology change, from carbon granules to carbon nanosheets, occurred at an annealing temperature of 1273 K. The unique carbon sheet morphology guaranteed a good specific capacitance of 246.4 F g⁻¹ at 0.5 A g⁻¹ in 1 M H₂SO₄ aqueous solution and an excellent rate capability with a retention of 87.9% at 5 A g⁻¹ as coin cell. The outstanding capacitance attributes to the combination of pseudocapacitance due to the N,O dual-doping and unique nanosheet morphology. Moreover, its outstanding cycling performance with 95% retention over 10,000 cycles at 10 A g⁻¹ and an acceptable energy density of 8.6 Wh kg⁻¹ at 0.2 A g⁻¹ make the N,O-codoped carbon nanosheet potent and promising electrode material for high performance supercapacitors.