NiCo2S4 flaky structured arrays on nickel foam were prepared hydrothermally by means of an anionexchange method, with NiCo2O4 nanorod arrays as precursors, and were directly applied as a binder-free supercapacitor electrode. Such a 3D structured electrode combines the advantages of both one dimensional and two dimensional materials, and can effectively improve the electrochemical performance. As a result, the as-prepared NiCo2S4 flaky structure electrode shows much enhanced electrochemical performance, with a high specific capacitance (2044 Fg(-1) at 1 Ag-1) and good cycling stability (capacity retention of 77% after 2000 cycles), suggesting its promising application for electrochemical capacitors. (C) 2015 Elsevier B.V. All rights reserved.