https://doi.org/10.1016/j.jpowsour.2025.237017
Abstract
The potential of TiO2 electrodes for supercapacitor applications is unlocked through a simple fabrication processthat has induced in-situ crystallization, with oxygen vacancy preservation, during anodization via a temperaturecontrolledwater bath for the electrolyte. The mixed-phase brookite-TiO2 (B) nanotube electrode fabricated at40°C delivers an exceptionally high energy density of 742 Whkg−1 without compromising power density (∼4.8kWkg−1) at a current density of 2.2 mAcm−2, across a wide potential window of 2V. The maximum areal specificcapacitance of the electrode ∼1382 mFcm−2 at 3.8 mAcm−2 is among the highest reported for TiO2 nanotubeelectrodes till date. The cyclic stability remains at 100 % for the first 9000 continuous cycles. A symmetric supercapacitorfabricated with the electrodes shows excellent performance delivering an energy density of 219Whkg−1 and a power density of 3.7 kWkg−1 at a current density of 1.7 mAcm−2. It yields a maximum areal capacitanceof 313 mFcm−2 or a gravimetric specific capacitance of 686 Fg-1 at a scan speed of 10 mVs−1. The remarkableperformance of this cost-effective and easily-reproducible electrode marks a breakthrough in the realm ofsupercapacitor electrode research, setting a new benchmark for future innovations.