High energy density of Sm-doped Na0.5Bi0.5TiO3-Sr0.7Bi0.2TiO3 relaxor ferroelectric ceramics

Dielectric ceramics have garnered significant attention in the realm of pulsed power system applications. Nevertheless, achieving a high recoverable energy density (W-rec) in dielectric ceramics remains challenging. Here, a high W-rec of 6.1 J cm(-3) was achieved in (1 - x)(0.6Na(0.5)Bi(0.5)TiO(3)-0.4Sr(0.7)Bi(0.2)TiO(3))-xSm(2)O(3) relaxor ferroelectric ceramics (RFCs). The enhanced W-rec stems from two factors: (I) the incorporation of Sm3+ with a small ionic radius can increase disorder at the A-site, thereby enhancing relaxor properties and reducing remnant polarization (P-r); (II) the introduction of Sm2O3 reducing vacancy and grain size, leading to an enhanced breakdown strength (E-b) of 470 kV cm(-1). This higher E-b facilitates increased maximum polarization (P-max). The increased E-b and the large polarization difference (Delta P = P-max - P-r) contribute to a substantial improvement in W-rec. Additionally, a novel approach was introduced to assess the relaxor characteristics by quantifying the degree of linear fitting of P-E loops. This study presents an effective strategy for designing high W-rec dielectric ceramics and introduces an innovative method for analyzing the relaxor properties of RFCs.