High-performance pseudocapacitor electrodes based on the flower-like nickel sulfide coated carbon nanofiber webs

Flower-shaped Ni3S2/Ni structures were synthesized on the surface of three-dimensional (3D) carbon fiber webs (CFWs) using electroless plating of Ni and subsequent sulfuration. The as-obtained product of this treatment was characterized using various techniques including scanning electron microscopy and X-ray diffraction, and was confirmed to indeed be Ni3S2/Ni-coated CFWs. Moreover, these webs were observed to have a unique architecture, consisting of a hierarchical porous structure with the flower-shaped morphology. This structure apparently enabled efficient ion diffusion and rapid electron transfer through the 3D CFW supports, as the Ni3S2/Ni-coated CFWs showed excellent electrochemical performances: a high areal capacitance of 240 mF/cm2 at current density of 1 mA/cm2, a high rate capability of 85.4% retention at current density of 15 mA/cm2, and good long-term stability (98% over 2000 cycles).