Synthesis of a hierarchical cobalt sulfide/cobalt basic salt nanocomposite via a vapor-phase hydrothermal method as an electrode material for supercapacitor

In this work, a hierarchical structured cobalt sulfide/cobalt basic salt nanocomposite is successfully synthesized by using cobalt basic salt nanowires as a precursor through a vapor-phase hydrothermal process. The as-obtained hierarchical structured cobalt sulfide/cobalt basic salt nanocomposite can be applied as an electrode material for supercapacitors, it exhibits a high specific capacitance of 1984 F g(-1) at a current density of 1 A g(-1), a good rate capability of 78.6% capacitance retention at a high current density of 20 A g(-1) and an excellent cycle stability of 90.2% capacitance retention after 5000 charge-discharge cycles. The specific capacitance of the cobalt sulfide/cobalt basic salt nanocomposite is much higher than that of the cobalt basic salt. The excellent electrochemical performances of the cobalt sulfide/cobalt basic salt nanocomposite can be attributed to its unique hierarchical nanostructure.