Hierarchical nanosheets-anchored-on-microsheets FeCo2S4 arrays as binder-free electrode for high-performance hybrid supercapacitor

The binary transition metal sulfides are highly desirable electrode materials for high-performance supercapacitors, thanks for their excellent electrochemical activity and electrical conductivity. Herein, the hierarchical FeCo2S4 arrays are designed and constructed on Ni foam, which consists of microsheets anchored nanosheets. The FeCo2S4 hierarchical structure provides high conductivity and abundant electroactive sites as well as facial and short ion transport paths. Therefore, the FeCo2S4 electrode achieves an excellent specific capacitance of 2488.50 F g(-1) (7.66 F cm(-2)) at 5 mA cm(-2), and a high level of cycle stability of 95.67% retention after 5000 cycles. The FeCo2S4//activated carbon (AC) device delivers the maximal energy density of 44.89 W h kg(-1) and the maximal power density of 4015.56 W kg(-1). The impressive electrochemical properties of hierarchical FeCo2S4 arrays make it a promising high-performance electrode for hybrid supercapacitors. (C) 2019 Elsevier B.V. All rights reserved.