Nickel sulfide nanosheets with high electrochemical performance were successfully synthesized by an electrochemical deposition method. It is interesting to notice that the size, thickness and surface area were simply tailored by adjusting the initial potential during synthesis without changing other reaction conditions. The highest electrochemical performance was achieved on the nickel sulfide sample prepared at initial potential of -0.9 V. This sample not only presented high specific capacitance at low current density (1958.0F g(-1) at 3.3 A g(-1)), but also exhibited excellent high rate performance (672.8F g(-1) at 98.7 A g(-1)). To the best of our knowledge, these values are in the highest level as compared with other works. The high electrochemical performance of nickel sulfide sample originates from its thin thickness. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.