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.