RGO/FeS composites on Fe foil were successfully prepared via a facile one-pot hydrothermal method, in which Fe foil acted as Fe source of FeS, reductant of GO and subsequent current collector. As-prepared RGO/FeS was directly served as the electrode of supercapacitor which exhibited a high specific capacitance of 900 mF cm(-2) (300 Fg(-1)) and a superior cyclability of 97.5% maximum capacity retention after 2000 cycles. Furthermore, an asymmetric supercapacitor (ASC) was assembled using Ni(OH)(2) as the positive electrode and RGO/FeS as the negative electrode. This ASC delivered a high power density of 20930.4 W kg(-1) with an energy density of 11.63 Wh kg(-1), or a high energy density of 27.91 Wh kg(-1) at the power density of 2093.18 W kg(-1), indicating RGO/FeS is a promising negative electrode of supercapacitor. (C) 2017 Elsevier Ltd. All rights reserved.