High Piezoelectricity and Thermal Stability in BiScO ₃ –PbTiO ₃ –Pb(Sn _1/3 Nb _2/3 )O ₃ Ceramics via Defect Engineering

ABSTRACT To improve high‐temperature piezoelectric performance, a defect engineering strategy was applied to 0.355BiScO 3 –0.615PbTiO 3 –0.03Pb(Sn 1/3 Nb 2/3 )O 3 (PSN–BS–PT) ceramics by substituting Sc 3+ with Zr 4+ . This introduces cation vacancies and lattice distortion, promoting a tetragonal–monoclinic (T–M) phase coexistence that facilitates polarization rotation. PFM, TEM, and HAADF‐STEM analyses reveal a complex coexistence of submicron and nanoscale domains induced by local symmetry variations. Consequently, the optimized PSN–BSZ 0.02 –PT ceramic exhibits outstanding properties: a high piezoelectric coefficient ( d 33 = 508 pC/N), large remnant polarization ( P r = 39 µC/cm 2 ), and a high Curie temperature ( T c = 437°C). Furthermore, it demonstrates excellent temperature stability with d 33 varying less than 15% up to 300°C and a depolarization temperature ( T d ) of ∼ 350°C. This defect engineering approach effectively lowers the domain reversal energy barrier, providing a viable route for designing advanced high‐temperature piezoceramics.