Supercapacitive performance of TiO(2) boosted by a unique porous TiO(2)/Ti network and activated Ti(3+)

TiO(2) has been reported to have considerable capacity through appropriate surface modification. Previous studies of TiO(2)-based supercapacitors mainly focused on anodized TiO(2) nanotubes and TiO(2) powder, even though the capacitance still lags behind that of carbon-base materials. In this work, a three-dimensional porous TiO(2)/Ti (PTT) network was constructed by anodic oxidation and its capacitance was boosted by subsequent aluminum-reduction process. Activated Ti(3+) was proved to be being successfully introduced into the surface of pristine PTT, resulting in the prominent enhancement of supercapacitive performance. An areal capacitance of 81.75 mF cm(−2) was achieved from Al-reduced PTT (Al-PTT) at 500 °C in 1 M H(2)SO(4) electrolyte, which was among the highest value of pure TiO(2)-based electrodes. Good electrochemical stability was also confirmed by the 3.12% loss of the highest capacity after 5000 CV cycles. More importantly, the activated Ti(3+)/Ti(4+) redox couple in modified TiO(2) is solidly confirmed by being directly observed in CV curves. The capacitive mechanism of the redox reaction is also studied by electrochemical tests. The construction of a 3D porous network structure and efficient Ti(3+) introduction provide an effective method to boost the supercapacitive performance of TiO(2)-based materials for energy storage applications.