A hydroxide-template strategy coupled with in-situ chemical activation is reported for the first time to fabricate porous carbon nanosheets (PCNSs) from coal tar. The thin PCNSs feature abundant short pores accessible for fast ion transport and high specific surface area up to 3235 m(2) g(-1) for ion adsorption. As electrodes for supercapacitors, the PCNSs show a high capacitance of 296.2 F g(-1) at 0.05 A g(-1) in 6 M KOH electrolyte, an excellent rate performance with a capacitance of 220.7 F g(-1) at 20 A g(-1) and a superior cycle stability with over 97.2% capacitance retention after 11000 charge-discharge cycles at 3.5 A g(-1). This work paves a new way for efficient fabrication of sheet-like carbon materials with tuned porous structure from polycyclic aromatic hydrocarbons for high performance supercapacitors. (C) 2017 Elsevier B.V. All rights reserved.