Composition-dependent electrical property of (1-x)Sr0.75Ba0.25Nb2O6-xPbZr0.52Ti0.48O3 solid solution ceramics

Solid solution ceramics of (1- x )Sr 0.75 Ba 0.25 Nb 2 O 6 - x PbZr 0.52 Ti 0.48 O 3 ( x = 0−0.4) were prepared and investigated. The phase evolves from tungsten bronze for x  = 0, coexisted tungsten bronze and pyrochlore at x  = 0.3, to pyrochlore for x > 0.3. As the results, the ceramics show dramatically composition dependent microstructure and electrical property. The grain shape changes from anisotropic pillar-like with maximum length-diameter ratio of 3.3 at x  = 0.2 to isotropic cubic-like for x > 0.2. At the same time, the maximum dielectric constant temperature tends to decrease with an exceptional increase at x  = 0.3 due to the coexisted phases. Interestingly, the x  = 0.3 ceramic endures ultrahigh breakdown strength of 340 kV/cm, which, together with enhanced polarization, results in maximum recoverable energy storage density of 3.0 J/cm 3 and energy storage efficiency of 81.5 % at room temperature.