It is well known that the electrochemical performances of electrode materials seriously depend on their shapes and structures. In this work, we synthesize NiO/NixSy microspheres by a simple hydrothermal route and vulcanization process. The as-obtained products are used as supercapacitor electrode materials. It delivers a capacitance of 1529.29 F g(-1) at 1 A g(-1). An asymmetric capacitor using NiO/NixSy as positive electrode is assembled, which keeps capacitive retention of 85.23% (10,000 cycles). The excellent electrochemical performance of NiO/NixSy electrode can be ascribed to the addition of sulfur and synergistic effect between NiO and NixSy structures. It shows that the as-prepared products can be potential electrode materials for emerging energy storage devices. (C) 2019 Elsevier Inc. All rights reserved.