Excellent energy storage performance in NaNbO3-based relaxor antiferroeic ceramics under a low electric field

Abstract

NaNbO₃-based antiferroelectric (AFE) ceramics have the prominent advantages of stable performance and low cost. However, its energy storage property is often remarkably limited by the hysteresis of the antiferroelectric to ferroelectric phase transformation. In this work, 0.88Na(Nb_1−xTa_x)O₃–0.12Bi_0.2Sr_0.7TiO₃ (x = 0–0.075) antiferroelectric ceramics were synthesized using a conventional mixed oxide route. Ta⁵⁺ were completely dissolved into the lattice of 0.88NaNbO₃–0.12Bi_0.2Sr_0.7TiO₃ to form a pure perovskite structure. With increased Ta content, the AFE orthogonal P phase was replaced by AFE orthogonal R phase progressively. Meanwhile, the dielectric constant curve showed relaxor-like properties. As a result, slender P–E curves with reduced hysteresis loss and decreased residual polarization were achieved. Interestingly, a large recoverable energy storage density (W_rec ~ 2.16 J cm⁻³) and high energy storage efficiency (η ~ 80.7%) were obtained simultaneously under a low driving electric field of 15 kV mm⁻¹ at doping ratio (x) of 0.075. In addition, the 0.88Na(Nb_0.925Ta_0.075)O₃–0.12Bi_0.2Sr_0.7TiO₃ sample exhibited excellent temperature stability, indicating an ideal candidate in future pulsed power capacitor.