Enhanced energy storage properties of lead-free (Ca0.5Sr0.5)(1-1.5x)LaxTiO3 linear dielectric ceramics within a wide temperature range

摘要

(Ca0.5Sr0.5)(1-1.5x)LaxTiO3 (x = 0.000, 0.050, 0.075, 0.100, 0.150) ceramics were successively fabricated by conventional solid state method. Structure characterization were detected by XRD and SEM, demonstrating the influence of La2O3 doping on the microstructure. In addition, this effect on relaxor behavior corresponding to resistivity of grain boundary was discussed by dielectric and impendance spectra. The determining band gap energy (E-g) was estimated by Ultraviolet-Visible Spectrophotometry in order to investigate the effect of band gap on the breakdown strength. The dielectric breakdown strength was found to significantly enhanced on the basis of Ca0.5Sr0.5TiO3 ceramics with La2O3 doping, the (Ca0.5Sr0.5)(0.8875)La0.075TiO3 samples possessed widest band gap (similar to 5.2 eV) and exhibited maximum breakdown strength of 370 kV/cm corresponding with a large recoverable energy storage density of 2.07 J/cm(3). Furthermore, the excellent stability of energy storage properties and ultrahigh energy efficiency of above 93% at wide frequency (1-1000 Hz) as well as high temperature (20-180 degrees C) was obtained for (Ca0.5Sr0.5)(0.8875)La0.075TiO3 ceramics, which reveal samples as good candidate for linear energy storage fileds.