Improved thermal stability of dielectric properties and energy storage properties of lead-free relaxor Ba_(1-x)La_xTi_0.89Sn_0.11O₃ ceramics

Environmentally friendly perovskite ceramics Ba_(1-x)La_xTi_0.89Sn_0.11O₃ with x = 0, 0.015, 0.025, and 0.035 (BLTSnx) were synthesized by solid-state reaction method. The enhanced energy storage properties were studied across the ferroelectric relaxor conversion. The pure perovskite structure of all prepared samples was confirmed by X-ray diffraction (XRD) analysis and the Raman spectroscopy technique. Scanning electron microscopy micrographs show a drastic decrease in the grain size in La-doped ceramics. Furthermore, the doped samples exhibit smeared phase transition and frequency dispersion in dielectric permittivity, typical for relaxors. The P-E hysteresis loops become thin with the increase of the La-doping, demonstrating the ferroelectric-relaxor phase conversion. The improved recovered energy density and the energy storage efficiency of 158.8 mJ/cm³ and 82.73 % were observed in the BLTSn2.5 sample at room temperature, respectively. These properties indicate that environmentally friendly BLTSn2.5 is a viable candidate for energy-storage capacitor applications near room temperature.