Effects of Parameters for Preparing Carbon Nanotubes on the Capacitances of Manganese-Cobalt-Zinc Oxide/Carbon Nanotube Electrodes

Abstract

A Co (catalyst)-Ti-coated silicon foil on which carbon nanotubes (CNTs) are directly grown by thermal chemical vapor deposition (CVD) with/without H 2 and using different temperatures/volume flow rates of NH 3 is optionally pretreated with hydrogen-plasma. Thereafter the CNTs are treated with nitrogen-plasma, and a manganese-cobaltzinc oxide film is deposited on the CNTs by radio frequency sputtering. For the CNT electrode, at the 100th cycle of potential cycling, its specific capacitance at a CNT growing temperature of 750°C is higher than those at 700 or 800°C and the higher the NH 3 flow rate while growing CNTs, the higher the specific capacitance. Furthermore, the specific capacitance of the manganese-cobalt-zinc oxide/CNT electrode for the CNTs grown in 50 cm 3 min −1 NH 3 is higher than that without NH 3 .