Aliovalent Sm-doping enables BNT-based realxor ferroelectric ceramics with > 90% energy efficiency

Dielectric capacitors as a physical power are critical components in advanced electronics and pulse power systems. However, achieving a high energy efficiency without sacrificing recoverable energy density remains a challenge for most dielectric materials. Taking advantage of aliovalent Sm³⁺ dope Ba_0.12Na_0.3Bi_0.3Sr_0.28TiO₃ (BNBST) relaxor ferroelectric at A-site, in this work, to design defect-induced phase/domain structure to improve polarization switching. A high energy efficiency of 91% together with a recoverable energy density of 2.1 J/cm³ has been achieved in Sm_0.07-BNBST ceramics at a low electric field of 114 kV/cm, exceeding other dielectric materials under the same electric field. Besides, Sm_0.07-BNBST ceramics exhibits good energy storage stability, endurance, and fast charging-discharging speed, demonstrating its great potential in electrostatic capacitor applications. This work provides an approach to achieving high-performance dielectrics through aliovalent rare earth doping and builds a close relationship between defect-engineered phase/domain structure and polarization switching for energy storage.