Nitrogen and phosphorus co-doped nonporous polybenzoxazine-based carbons (C/P-Cs) were fabricated using polybenzoxazine as a carbon precursor and melamine polyphosphate as a N/P co-doped precursor. The surface contents of the nitrogen and phosphorus of the C/P-Cs were as high as 5.5 atom% and 5.1 atom%, respectively, which enhanced the specific capacitance, rate capability and cycling stability of the C/P-Cs electrode effectively. The optimal C/P-Cs electrode exhibited high specific capacitances of 203.0 F g(-1) at a current density of 0.5 A g(-1) and 173.2 F g(-1) at a current density of 20 A g(-1). The capacitance retention of the C/P-Cs electrode still maintained 90.1% after 5000 cycles at a current density of 5 A g(-1). The supercapacitor assembled using the optimal C/P-Cs electrodes exhibited a maximum energy density of 11.45 Wh kg(-1) at a power density of 50W kg(-1) and a maximum power density of 25 kW kg(-1) at an energy density of 5.55 Wh kg(-1). The capacitance retention of the supercapacitor sill retained 79.9% after 10 000 cycles at a current density of 5 A g(-1). Thus, the C/P-Cs presented great potential in supercapacitor applications. (c) 2018 The Electrochemical Society.