Carbon Nanotubes Grown on Nanoporous Alumina Templates/Aluminum Foil for Electrodes of Aluminum Electrolytic Capacitors

Carbon nanotubes (CNTs) were directly grown on nanoporous alumina templates/aluminum foil by chemical vapor deposition using different temperatures and times. Next, aluminum was sputtered onto the nanoporous alumina templates with grown CNTs/aluminum foil with grown CNTs by varying the sputtering time and power. Finally, aluminum oxide was formed by anodizing in an ammonium adipate solution. A higher capacitance (2159 mu F/cm(2)) as well as a superior operation voltage (55.10 V) with the pore bottom of the alumina templates as a substrate and a higher capacitance (3426 mu F/cm(2)) as well as a superior operation voltage (38.44 V) with an aluminum foil substrate were obtained at better/the best CNT growing conditions (600 degrees C/60 min) and better sputtering conditions (65 W and 4 h). Furthermore, the higher the CNT growing temperature, the higher the capacitance. The capacitance decreased with increasing sputtering power and time, but the operation voltage increased with increasing sputtering power and time.