Synthesis and Investigation of Electrochemical Studies on Thulium Tellurite (TmTeO₃) for Supercapacitor Electrode Application

Thulium tellurite ([Formula: see text]) is synthesized by hydrothermal method. It exhibits nearly cuboid-shaped particles along with triangular particles. [Formula: see text] is found to be monoclinic. The energy gap is 5.87[Formula: see text]eV, the Urbach energy value is 0.287[Formula: see text]eV and the refractive index is 1.881. The size of the particle is determined as 107[Formula: see text]nm. Optical transitions between energy levels assign absorption and emission peaks. Tm, was found in the oxide matrix as Tellurite. Magnetic susceptibility between 20[Formula: see text]K and 300[Formula: see text]K decreases with temperature, reaches saturation and aligns all Thulium spins. M–H curve confirms paramagnetic nature at 300[Formula: see text]K and feeble ferromagnetic nature at 77[Formula: see text]K. Cyclic voltammogram and chronopotentiometry analysis exhibit pseudo-capacitive behavior. The potential window is 0.82. Specific capacitance is found to be 87[Formula: see text]F/g. Chronopotentiometry analysis shows 55[Formula: see text]F/g specific capacitance. Impedance analysis shows a pseudo-capacitive nature. [Formula: see text] symmetrical supercapacitor device is fabricated with potential window of 1.52[Formula: see text]V. A specific capacitance of 37.75[Formula: see text]F/g at 1 A/g, energy density 6.055[Formula: see text]Wh kg[Formula: see text] and power density 760.99[Formula: see text]W kg[Formula: see text] was achieved. Impedance analysis shows low series resistance of 2.567[Formula: see text][Formula: see text] and charge transfer resistance of 0.473[Formula: see text][Formula: see text]. Cyclic performance with 80% specific capacitance retention is observed after 5000 cycles. The [Formula: see text] symmetric supercapacitor electrodes possess good electrochemical properties due to wider potential window, long cycle stability and notable energy density.