Superior cycling stability of a crystalline/amorphous Co3S4 core-shell heterostructure for aqueous hybrid supercapacitors

In this article, a novel crystalline/amorphous Co3S4 core-shell heterostructure supported on nickel foam is fabricated through a facile method. Due to the unique structure of the crystalline Co3S4 core that provides stable mechanical support and surface-active sites and the amorphous shell that facilitates diffusion and reaction of electrolyte ions, the obtained crystalline/amorphous Co3S4 electrode shows a superior pseudocapacitive performance of 2.65 F cm(-2) (2038.5 F g(-1)) at a current density of 5 mA cm(-2) and even 1.81 F cm(-2) (1392.3 F g(-1)) at 50 mA cm(-2). In addition, the Co3S4//AC exhibits a relatively high energy density of 54.78 W h kg(-1) at a power density of 400.02 W kg(-1) and excellent cycling performance (about 94.8% capacitance retention over 32500 cycles). The kinetic analysis reveals a diffusion controlled faradaic characteristic of Co3S4 (73.21% diffusion-controlled contribution). Moreover, the fabrication process presented in this work is facile, cost-effective, and environmentally benign, offering a feasible solution for fabricating next-generation high-performance energy storage devices.