Experimental and DFT studies on energy storage efficiency of Ag+ doped barium titanate thin films (Ba1-xAgxTiO3 (x = 0.00, 0.10, 0.20))

The current study investigated the energy storage capacity of Ag⁺ doped two-dimensional (2D) barium titanate perovskite, using combinations of experimental theoretical techniques. Data from electrochemical impedance spectra and DFT geometrical optimization revealed the existence of +1 valency state by Ag ions. With the obtained parameters, highest efficiency was attributed to 0.10 mol% Ag doped 2D BaTiO₃ variant, due to reduced defect and suppressed ferroelectric order. Notably, the piezoelectric response showed slight decreasing trend with Ag⁺ content, reaching the lower value of 223 pC/N with 0.20 mol% Ag. Reduction in the values of T_c due to Ag ⁺ ions indicates reduced polarization and high dielectric permittivity. In all samples used, good relationship existed between recoverable-energy storage and efficiency, owing to remanent polarization, hysteresis loss and dielectric breakdown. Moderate doping improved breakdown strength, leading to reduced P_r which increases $W_{rec}$ values with relatively 1.12 Jcm⁻³. The conducted experimental and DFT analysis revealed good alignment between some considered structural and energy storage parameters, such as lattice constants, piezoelectricity, and curie temperature.