▎ 摘　　要

Porous cobalt sulfide (CoSx)/reduced graphene oxide (rGO) hybrid films has been fabricated as a flexible freestanding supercapacitor electrode via the co-assembly and sulfidation of 2D metal organic framework (MOF) nanoflakes and graphene oxide (GO). Firstly, zeolitic imidazolate-67 (ZIF-67) nanocubes were added into the aqueous solution of GO to yield a mixed dispersion of ZIF-67 and GO (ZIF-GO). It was found that the morphology of ZIF-67 changed from nanocubes to 2D nanoflakes owing to the concentration change, which favored the formation of hybrid film. Secondly, the sandwich-like GO/ZIF-GO/GO hybrid film was fabricated by the successive vacuum membrane filtration of GO, ZIF-GO, and GO solutions. Finally, the hybrid film was sulfidized via a hydrothermal process using thioacetamide as the sulfur source. This process also led to the reduction of GO to rGO. The resulting rGO/CoSx-rGO/rGO hybrid film was shown to have good electro-chemical performance because it combined the good pseudocapacitor property of cobalt sulfide as well as the good conductivity and electric double layer capacitor property of rGO. In addition, an all-solid-state asymmetric supercapacitor (aSC) was assembled using rGO/CoSx-rGO/rGO hybrid film and active carbon as the positive and negative electrodes, respectively. It exhibited an energy density of 10.56 Wh kg(-1) and a power density of 2250 W kg(-1). Also, it retained 92.8% of initial capacitance after 10,000 cycles. The good electrochemical performance revealed that the resulting aSC has great potential in the practical application of supercapacitors. (c) 2021 Elsevier B.V. All rights reserved.