▎ 摘　　要

Electrode materials with high capacitance and outstanding stability are critical for developing flexible supercapacitors (FSCs), which have recently received increasing attention. Herein, a hierarchical CuS/three dimensional graphene (3DG) composite was prepared, which possessed a decent specific capacitance of 249 F g(-1) at a current density of 4 A g(-1) and remarkable cycling stability with 95% retention after 5000 charge-discharge cycles. Moreover, a flexible solid-state supercapacitor was assembled with binder-free electrode materials and exhibited an energy density of 5 W h kg(-1) at a power density of 450 W kg(-1). The peculiar hierarchical structure of CuS could provide abundant contact area between the active material and electrolyte, thus shortening diffusion distance. The high conductivity of 3DG could reduce overall resistance and improve the rate performance of the electrode materials. Therefore, the hierarchical CuS/3DG composite has promising application potential in flexible energy storage devices. (C) 2017 Elsevier Ltd. All rights reserved.