Nitrogen-doped porous monolithic carbon (NDPMC) is obtained from biomass-derived activated carbon/polyacrylonitrile composite for the first time via a template-free thermally induced phase separation (TIPS) approach followed by KOH activation. The electrochernical results indicate that NDPMC possesses ultrahigh specific capacitance of 442 F g(-1) at 1 A g(-1), excellent rate capability with 81% retention rate from 1 to 100 A g(-1) and outstanding cycling stability with 98% capacitance retention at 20 A g(-1) after 5000 cycles. Furthermore, the evaluation of NDPMC on the practical symmetrical system also exhibits desired electrochemical performances. The novel composite carbon displays remarkable capacitance properties and the feasible, low-cost synthetic route demonstrates great potential for large-scale production of high-performance electrode materials for supercapacitors. (C) 2017 Elsevier B.V. All rights reserved.