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 (T_c) 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 Bi₄Ti_2.93(Zn_1/3Nb_2/3)_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 T_c = 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.