N/O co-doped hierarchically porous carbon with three-dimensional conductive network for high-performance supercapacitors

Heteroatom doping is a significant modification of carbon materials for electrodes in storage device and co-doping has synergistic improvement effect. This work reports a N/O co-doped porous carbon (CPK800) from crosslinking sodium carboxymethyl cellulose and poly (m-phenylene diamine). The material characterization reveals its large specific surface area of 1501.3 m² g⁻¹ with optimum micro- and mesopore distribution, partially graphitized carbon and high N, O concentration. This carbon has 3D interconnected porous structure and internal conducting network providing rapid ion and electron transportation. Take these advantages, it exhibits high capacitance of 358 F/g at 1 A g⁻¹, an excellent rate retention of 70.8% at a high current density of 20 A g⁻¹, and superior cyclic stability of 97.8% capacitance retention after 10,000 cycles at 10 A g⁻¹ as an electrode material in 3 M KOH electrolyte. Moreover, the assembled symmetric supercapacitor device (CPK800//CPK800) delivers a high energy density of 11.5 Wh kg⁻¹ at a power density of 326.8 W kg⁻¹ and still have energy density of 8.9 Wh kg⁻¹ at a very high power density of 6.8 kW kg⁻¹. The well-developed structure and outstanding electrochemical performance demonstrate the promising potential of CPK800 as electrode material for advanced energy storage devices.