P–E hysteresis loop going slim in Ba_0.3Sr_0.7TiO₃-modified Bi_0.5Na_0.5TiO₃ ceramics for energy storage applications

(Ba_0.3Sr_0.7)_x(Bi_0.5Na_0.5)_1-xTiO₃ (BS_xBNT, x = 0.3–0.8) ceramics were prepared to investigate their structure, dielectric and ferroelectric properties. BS_xBNT ceramics possess pure perovskite structure accompanied from a tetragonal symmetry to pseudo-cubic one with the increase of x value, being confirmed by X-ray diffraction (XRD) and Raman results. The T_m corresponding to a temperature in the vicinity of maximum dielectric constant gradually decreases from 110 ℃ (x = 0.3) to –45 ℃ (x = 0.8), across T_m = 36 ℃ (x = 0.5) with a maximum dielectric constant (ɛ_r = 5920 @1 kHz) around room temperature. The saturated polarization P_s gradually while the remnant polarization P_r sharply decreases with the increase of x value, making the P–E hysteresis loop of BS_xBNT ceramics goes slim. A maximum difference between P_s and P_r (P_s–P_r) is obtained for BS_xBNT ceramics with x = 0.5, at which a high recoverable energy density (W_rec = 1.04 J/cm³) is achieved under an applied electric field of 100 kV/cm with an efficiency of η = 77%. Meanwhile, the varied temperature P–E loops, fatigue measurements, and electric breakdown characteristics for the sample with x = 0.5 indicate that it is promising for pulsed power energy storage capacitor candidate materials.