Template synthesis of C@NiCo2O4 hollow microsphere as electrode material for supercapacitor

Composite C@NiCo2O4 hollow microspheres (HSs) as electrode material were prepared via a two-step strategy of hard-template induced hydrothermal synthesis and calcination, in which SiO2@RF (resorcinol-formaldehyde resin, RF) sphere and hexamethylenetetramine (HMT) were used as hard template, and precipitant; Ni(NO3)2·6H2O and Co(NO3)2·6H2O as nickel and cobalt source, respectively. The resultant samples are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) patterns, XPS and N2 adsorption and desorption. The prepared C@NiCo2O4 material possess large specific surface area of 127.61 m2 g−1 and porous structure. The electrochemical measurements show that the C@NiCo2O4 exhibit a large specific capacitance of 404 F g−1 at the current density of 1 A/g, a good cyclic stability with a capacitance retention of 87.1% after 1000 cycles of charge-discharge and a low resistance.