Enhanced recoverable energy storage density and high efficiency of SrTiO3-based lead-free ceramics

In this study, (1−x)SrTiO3-x(Bi0.48La0.02Na0.48Li0.02Ti0.98Zr0.02O3) [(1−x)ST-xBLNLTZ] lead-free ceramics with x = 0–0.4 were designed and fabricated using the tape casting process and the subsequent conventional solid-state sintering method. The (1−x)ST-xBLNLTZ ceramics are characterized by the excellent frequency stability of the dielectric constant, large maximum polarization (Pmax), low remnant polarization (Pr), and slim polarization-electric field (P-E) loops. For the composition of x = 0.4, Pmax is increased to 30.35 μC/cm2, 3.82 times higher than that of pure SrTiO3 (7.95 μC/cm2). The breakdown strength is larger than 200 kV/cm for all the samples. The sample with x = 0.1 exhibits a high recoverable energy storage density (Wrec) of 2.59 J/cm3 and a high energy storage efficiency (η) of 85% simultaneously. The results demonstrate that the (1−x)ST-xBLNLTZ ceramics are promising lead-free materials for high energy storage applications.