Enhancing the electrochemical performance of nickel cobalt sulfides hollow nanospheres by structural modulation for asymmetric supercapacitors

The development of nickel cobalt sulfides electrodes with excellent electrochemical performance is important for supercapacitor applications. In this study, we constructed well-defined hierarchical nanosheet-built NiCo2S4/Co9S8 hollow nanospheres based on morphology and structural engineering. A combination of structural and compositional advantages endowed NiCo2S4/Co9S8 hollow nanospheres with enhanced electrochemical performance with favorable capacitance of 1008 F g(-1) at 1 A g(-1), exceeding that of single-component NiS (616 F g(-1) at 1 A g(-1)) and Co3S4 (430 F g(-1) at 1 A g(-1)). Furthermore, an assembled asymmetric supercapacitor (ASC) comprising NiCo2S4/Co9S8 hollow nanospheres and activated carbon achieved a high energy density up to 36.7 Wh kg(-1) at 800 W kg(-1), suggesting that it could be a promising electroactive material for energy storage devices. (C) 2019 Elsevier Inc. All rights reserved.