https://doi.org/10.1016/j.jpcs.2025.113425
(Accepted Nov 2025, Published Dec 2025)
Metal-doped mixed-phase TiO2 nanotube (TNTA) electrodes with enhanced performance characteristics for application in supercapacitors were developed by an innovative ”water-bath temperature controlled anodization” technique. The 4.9 % Mn-doped TNTA electrodes exhibited a high specific capacitance of 723.6 mF cm−2/1381.6 F g−1 at a current density of 6.3 mA cm−2, with a corresponding energy density of 276.3 Wh kg−1 and a power density of 7.2 kW kg−1, in a potential window of 1.2 V. Consistently high performance was observed across varying doping percentages and wider potential windows (PWs). An asymmetric supercapacitor with Mn-TNTA as the negative electrode and an activated conducting carbon cloth as the positive electrode achieved a specific capacitance of 192.7 F g−1, and energy and power densities of 91.5 Wh kg−1 and 1.1 kW kg−1, in a 2 V potential window. A superior asymmetric supercapacitor comprising MnO2-nanofibres modified TNTA as the positive electrode and Fe2O3-nanoparticles overlaid TNTA as the negative electrode, demonstrated a high specific capacitance of 286.6 mF cm−2/278.7 F g−1 and maximum energy and power densities of 170.7 Wh kg−1 and 1.9 kW kg−1 respectively. The device exhibited excellent cyclic stability over 5000 cycles with negligible performance degradation within a 2.1 V potential window. A single ASC powered a red LED (forward voltage: 1.8 V) for 9 min 30 s, while two ASCs in series powered the same red LED for 2 h 30 min and a violet LED (forward voltage: 3.7 V) for 1 h 9 min before complete dimming.
