Ultrahigh energy-storage potential under low electric field in bismuth sodium titanate-based perovskite ferroelectrics

Relaxor ferroelectrics are receiving an increasing amount of attention because of their superior energy-storage density. Due to environmental concerns, lead-free alternatives are highly desirable, with bismuth sodium titanate highlighted for its energy-storage applications. Here, we realized an enhancement in energy-storage performance with a recoverable energy density (W-rec) of 2.42 J cm(-3) (low electric field of E = 143 kV cm(-1)) in {Bi-0.5[(Na0.8K0.2)(0.90)Li-0.10](0.5)}(0.96)Sr-0.04(Ti0.975Ta0.025)O-3 ceramics by a hot-pressed sintering (HPS) method, which is greatly superior to the reported perovskite ceramics under similar electric fields. In addition, excellent fatigue and thermal stabilities (variation of W-rec 0.047% after 10(5) cycles and W-rec > 2 J cm(-3) over 25-175 degrees C) can be observed. The HPS method greatly increases the dielectric breakdown strength (DBS approximate to 143 kV cm(-1)) because of a denser structure consisting of large and small grains, which is superior to those (78-97 kV cm(-1)) of spark plasma sintering (SPS), conventional air sintering (CAS), and MnO aids sintering (AS) methods. In addition to the contribution of the enhanced breakdown strength, the ultrahigh energy-storage density is also due to the almost complete RE to FE transition resulting from strain, polarization, and current density versus electric field (S-E, P-E, j-E) loops. Interestingly, a giant strain of 0.65% can also be found by the HPS method. In particular, a conceptual model based on the nature of relaxor ferroelectrics is employed to understand the excellent energy-storage properties observed in this work. We believe that the findings in this work may provide future tips and guidance for this direction of study.