Template synthesis of 1D hierarchical hollow Co3O4 nanotubes as high performance supercapacitor materials

Abstract

One-dimensional (1D) hierarchical hollow Co3O4 nanotubes have been controllably fabricated via a facile two-step strategy including template-hydrothermal reaction and calcination, in which cobalt sulfate heptahydrate, guanidine hydrochloride and activated carbon are used as cobalt precursors, precipitant and hard template, respectively. The resultants of Co3O4 are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) patterns and N2 adsorption and desorption. The novel precipitant guanidine hydrochloride and hard template activated carbon contributed to the interesting morphology, and plus Kirkendall effect leading to producing hollow structure with hierarchical porous. The electrochemical properties of prepared different Co3O4 samples are evaluated and compared through cyclic voltammetry (CV), charge–discharge and electrochemical impedance spectroscopy (EIS) in 2.0M KOH electrolytic solution. The results show that the 1D hierarchical hollow Co3O4 nanotubes exhibit a large specific capacitance of 1006Fg−1 at 1Ag−1, an outstanding cyclic stability with a capacitance retention of 91% after 1000cycles of charge–discharge and a low resistance.