Temperature-dependent broadband dielectric and ferroelectric properties of Ba(1-x)SrxTiO3 ceramics for energy storage capacitor applications

In the recent past, high energy storage and fast discharge capacitors have attracted considerable attention among the scientific community. In this context, a series of lead-free barium titanate-based ceramics with composition Ba(1-x)SrxTiO3 (x = 0.00-0.50) are synthesized using a solid-state reaction method to study their storage and discharge characteristics. The ceramics were sintered at different temperatures, and the ceramics sintered at 1300 degrees C/2 h showed the maximum relative density with tetragonal symmetry for x <= 0.3 and cubic symmetry for x >= 0.4. The uniformity in grain sizes for the ceramics improved with an increase in Sr content till x = 0.3. The pristine BaTiO3 (BTO) displayed three humps at - 60, 20, and 125 degrees C corresponding to rhombohedral-tetragonal-cubic phase transitions, respectively, and T-c shifted to room temperature with an increase in Sr concentration. The recoverable energy density for x = 0.3 goes around 29 mJ/cm(3) with an energy efficiency of 56.1%. For pure BTO, the recoverable energy density obtained is 31.2 mJ/cm(3) with an energy efficiency of 38% at an electric field of 15 kV/cm. The samples' diffusive coefficient is obtained by fitting the modified Curie-Weiss law and found that all the samples exhibited ferroelectric behavior as the gamma value is around one. This study focused on the structural, microstructural, broadband dielectric spectroscopy and the ferroelectric properties of Sr-modified BaTiO3 ceramics. Such studies form an extensive evaluation of the properties of the synthesized ceramics for energy storage applications.