Nanotube array supercapacitors have been designed for electric double layer and redox capacitance applications using bare titania nanotubes and electroactive nickel oxide or ruthenium oxide modified titania nanotube composite electrodes. Titania nanocomplexes with nanoribbon-nanotube and nanowire-nanotube structure have been synthesised through a two-step anodisation process. The well-defined titania has been applied for electric double layer supercapacitor applications. This book presents and discusses current research in the creation and application of nanotube array supercapacitors.