Self-Template Synthesis of Nickel Cobalt Sulfide Hollow Nanotubes for High-Performance Battery-Type Supercapacitors

Abstract

In this work, nickel cobalt sulfide with hollow tubular structure was synthesized by solvothermal and subsequently anion-exchange processes. The nickel cobalt sulfide nanotubes processed high specific capacity (531.9 C g −1 at 0.5 A g −1 ) when it directly used as electrode material. Furthermore, an asymmetric supercapacitor was fabricated with nickel cobalt sulfide nanotubes as a positive electrode and active carbon as a negative electrode. The asymmetric device exhibited a maximum energy density of 25.7 Wh kg −1 and a maximum power density of 4315 W kg −1 , and excellent cycling performance (84.3% capacity retention) over 10000 cycles. The excellent electrochemical behaviors indicated that nickel cobalt sulfide nanotubes were highly desirable for high capacity energy storage devices.