Effect of film thickness on dielectric properties and energy storage performance of Ba0.95Ca0.05Zr0.3Ti0.7O3 thick films prepared by tape casting

Abstract

Free-standing Ba0.95Ca0.05Zr0.3Ti0.7O3 thick films with varying thicknesses (90–200 μm) were prepared by tape casting technology. The thick films exhibited dense microstructure with fine and uniform grains (~ 1 μm). The dielectric properties, dielectric breakdown strength, and energy storage performance of the thick films were examined. The dielectric properties of the thick films were essentially unaffected by changing film thickness. The thick films with varying thicknesses showed similar dielectric constant and loss values, ferroelectric phase transition behavior, and dielectric nonlinearity. In contrast, the dielectric breakdown strength and energy storage performance were substantially dependent on film thickness. The dielectric breakdown strength and recoverable energy storage density were increased with reducing film thickness, while the energy storage efficiency at an identical applied electric field was enhanced. The film with a thickness of 90 μm achieved the optimal energy storage performance among the specimens investigated, exhibiting a recoverable energy storage density of 1.1 J/cm3 and an energy storage efficiency of 81.7% at an electric field of 260 kV/cm. The thickness dependence of the dielectric breakdown strength and energy storage performance was explained with respect to presence of oxygen vacancies in the lattice.