Energy storage properties and electrocaloric effect of Ba0.65Sr0.35TiO3 ceramics near room temperature

Ba0.65Sr0.35TiO3 (BST) ceramics were synthesized by sol-gel route. The diffusion phase transition (DPT) characteristic was found in the temperature range from 150 to - 35 A degrees C. The value of the DPT parameter gamma values are 1.53 and 1.75, respectively at applied dc field of 0 and 16.7 kV/cm. It is implied that the phase transition of BST ceramics become more diffuse under the applied electric field. Temperature dependent polarization-electric field hysteresis loops were studied. It was found that the energy storage properties and electrocaloric effect near room temperature were the function of electric fields. The maximum value of recoverable energy density was 0.2812 J/cm(3) with energy storage efficiency (eta) of 78.67% obtained at room temperature under an electric field of 75 kV/cm. The largest eta can achieve 98% under low electric field of 50 kV/cm. A large electrocaloric temperature change (Delta T-max = 0.49 K) near room temperature was obtained by indirect method. Taken together, the ceramics have a promising candidate for energy-storage applications and cooling systems in the room temperature.