Preparation of highly capacitive polyaniline/black TiO2 nanotubes as supercapacitor electrode by hydrogenation and electrochemical deposition

A combination method of hydrogenated reduction and electrochemical deposition is employed to prepare highly capacitive polyaniline/black TiO2 nanotubes (PANI/H-TiO2 NTs) for supercapacitor. PANI/H-TiO2 NTs shows capacitance of 999 F g−1 at the current density of 0.6 A g−1. To the best of our knowledge, this result is the highest value based on TiO2 nanotubes (TiO2 NTs) or its composites (PANI/TiO2 NTs) for supercapacitor electrode. Moreover, PANI/H-TiO2 NTs also shows remarkable long-term cycling stability with only 29.8% reduction of the initial capacitance at a current density of 24.0 A g−1 after 2000 charge-discharge cycles, as well as great rate capability. The electrochemical impedance spectroscopy of PANI/H-TiO2 NTs shows that this electrode has low resistance. The solution resistance and charge-transfer resistance is as low as 0.1554 and 2.723 Ω cm−2, respectively, which indicate the better electronic transport ability and high charge-transfer rate of PANI/H-TiO2 NTs.