Super-Long Life Supercapacitors Based on the Construction of Ni foam/graphene/Co3S4 Composite film hybrid electrodes

• Formation of continuous Co3S4 films with hollow Co3S4 nanospheres on the surface of graphene.
• Multilayer-structured can provide mechanical supported.
• 3D graphene can improve the stability during charge and discharge processes with large currently density.

Supercapacitors have been extensively studied because of their higher power density and higher energy density. Recently, much attention has been focused on the synthesis and application of new materials with superior electrochemical performance for practical applications. Here, we presented a simple and cost-effective synthesis multilayer-structured three-dimensional (3D) Ni foam/graphene/Co3S4 composite film (Ni/G/CS) and used it as electrode for supercapacitor. The Co3S4 film consisted of small-diametered hollow nanospheres that clustered continuously together. The multilayer-structured 3D Ni/G/CS electrode combines merits of large specific surface areas of hollow nanospheres, extraordinary electrical properties and extremely high chemical stability of graphene, and highly mechanical stability properties of Ni foams. The electrodes provided extremely high values of capacitance and superior long-term cycle stability with the capacitance retention rate of 97.8% after 8000 cycles at a large charge-discharge current density.