Ion-Pair Engineering-Induced High Piezoelectricity in Bi₄Ti₃O₁₂-Based High-Temperature Piezoceramics

High-temperature piezoceramics are highly desirable for numerous technological applications ranging from the aerospace industry to the nuclear power sector. However, it is a grand challenge to achieve excellent piezoelectricity and high Curie temperature (Tc) simultaneously because there is a contradiction between the large piezoelectric coefficient and high Curie temperature in piezoceramics. Here, we provide a perspective via B-site ion-pair engineering to design piezoceramics with high performance for high-temperature applications. In bismuth-layered Bi4Ti2.93(Zn1/3Nb2/3)0.07O12 ceramics, high piezoelectricity of d33 = 30.5 pC/N (more than four times higher than that of pure Bi4Ti3O12 (d33 = 7.3 pC/N) ceramics) in conjunction with excellent thermal stability, high Curie temperature Tc = 657 °C, and large dc resistivity of ρ = 1.24 × 107 Ω·cm at 500 °C (three orders of magnitude larger than that of the pure Bi4Ti3O12 ceramics) are achieved by B-site Nb5+-Zn2+-Nb5+ ion-pair engineering. Excellent piezoelectricity is ascribed to sufficient orientation of the fine lamellar ferroelectric domain with the introduction of Nb5+-Zn2+-Nb5+ ion-pairs. The good temperature stability of d33 originates from the stability of the crystal structure and the robustness of the oriented ferroelectric domain. The significantly improved resistivity is due to the restricted mobility of oxygen vacancies. This work presents a brand-new technique for achieving high-temperature piezoceramics with high performance by B-site ion-pair engineering.