Formation of a Flower-Like Co-Mo-S on Reduced Graphene Oxide Composite on Nickel Foam with Enhanced Electrochemical Capacitive Properties

摘要

Transition metal sulfides have attracted considerable attention due to their excellent electrochemical performance for supercapacitors. Herein, we prepared a Co3S4/CoMo2S4 (Co-Mo-S) composite on reduced graphene oxide/Ni foam (RGO/NF) with unique flower-like morphology through a carefully time-controlled sulfurization process. It was found that the vulcanization time has a great influence on the morphology and electrochemical properties of the composites. After 3 hours of vulcanization, the as-prepared Co3S4/CoMo2S4@RGO/NF electrode exhibited a superior specific capacitance of 2530.4 F g(-1) at a current density of 1 A g(-1), as well as excellent cycling stability with 78.8 % retention of the initial capacitance even after 6,000 cycles at a current density of 10 A g(-1). An asymmetric device was assembled employing the Co3S4/CoMo2S4@RGO/NF composite as a positive electrode and activated carbon (AC) as a negative electrode. The device delivered a maximum energy density of 59.0 Wh kg(-1) at a power density of 640 W kg(-1) and a high cycling performance (90.7 % capacitance retention after 6,000 cycles). These results demonstrate the promising potential of Co-Mo-S@RGO/NF as binder-free, high-performance electrode in renewable energy storage systems.