Fabrication and supercapacitive performance of long anodic TiO2 nanotube arrays using constant current anodization

A galvanostatic anodization is used to prepare long TiO2 nanotube arrays (TNTAs). TNTAs of over 100 μm in length, with similar nanotube size and structural regularity to the classic TNTAs made from potentiostatic mode, are achieved at 10 mA cm− 2. After a post-anodization in a H3PO4-based electrolyte, the TNTAs with long nanotubes exhibit good adhesion to Ti substrate. The as-prepared long TNTAs yield a larger areal capacitance of 128.4 mF cm− 2. Further, the long TNTAs possess a higher surface area, making them suitable as support templates for other active materials.