Enhanced near-ambient temperature energy storage and electrocaloric effect in the lead-free BaTi_0.89Sn_0.11O₃ ceramic synthesized by sol–gel method

Lead-free perovskite materials with high performance have high potential in clean energy storage applications and developments of electrocaloric devices. This work reports structural, dielectric, ferroelectric, energy storage, and electrocaloric properties near the ambient temperature in barium stannate titanate (BaTi_0.89Sn_0.11O_3, BTS₁₁) ceramic prepared by a sol–gel method. A single perovskite structure formation was confirmed using the X-ray diffraction analysis. Average grain size of 18.5 µm was found by the mean of the SEM micrograph with a density of 5.91 g/cm³. The multiphase coexistence at very near ambient temperature was proved using temperature-dependent micro-Raman measurements and differential scanning calorimetry. The BTS₁₁ ceramic exhibits a high dielectric constant of 15,460 and a low dielectric loss (< 0.055) in a broad temperature range. Moreover, a high energy storage density of 122 mJ/cm³ was shown with an efficiency of 79%, a maximum value of electrocaloric temperature change (ΔT) of 0.86 K, and finally, an electrocaloric responsivity (ΔT/ΔE) of 0.24 K.mm/kV at the external electric field change of 35 kV/cm near ambient temperature. The enhanced dielectric, ferroelectric, and electrocaloric properties make BTS₁₁ ceramics a great candidate for solid-state cooling technology and high energy storage applications near ambient temperature.