▎ 摘　　要

The large-size graphene-like porous carbon nanosheets (LGPCN) with controllable N-doped surface are successfully prepared by using a simple and effective integrated "self-template" and "designing" strategy through KOH activation. Biomass-sugarcane bagasse pith and chitosan are used as self-template carbon source and controlled nitrogen source, respectively. The relationship between structure of the LGPCN-X (X represents the activation temperature) and its electrochemical performance at different activation temperatures is explored in detail. The large-size multiscale wrinkled nanosheets architecture, high surface area, and appropriate controllable surface nitrogen doping state of the LGPCN-800 shows the best electrochemical performance in 6 M KOH. The largest specific electrode capacitance is about 339 F g(-1) (at 0.25 A g(-1)), which still as high as 280 F g(-1) at 100 A g(-1). The maximum energy density is about 11.77 Wh kg(-1) at a power density of 34.11 W kg(-1). The LGPCN-800 also shows an excellent cycling stability with 97.9% capacitance retention after 10,000 cycles. (C) 2017 Elsevier Ltd. All rights reserved.