Simultaneous enhancement of piezoelectric performance and Curie temperature in high-temperature Bi₄Ti₃O₁₂ piezoceramics through A/B site co-doping

For Bi₄Ti₃O₁₂ (BIT) high-temperature piezoceramics, improving piezoelectric performance often comes at the expense of a reduced Curie temperature. In this study, a series of Bi_4−xCe_xTi_2.97(Cr_1/3Ta_2/3)_0.03O₁₂ (x = 0, 0.02, 0.04, 0.06, and 0.08) ceramics were synthesized using the solid-state reaction method, and their phase structure, microstructure, piezoelectric properties, and conduction mechanisms were systematically analyzed. By employing a B-site non-equivalent co-doping strategy and introducing Ce ions into the A-site, we achieve a synergistic increase in the piezoelectric performance, Curie temperature, and high-temperature resistivity of BIT-based ceramics. This A/B site multi-co-doping significantly enhances the electrical properties by reducing the oxygen vacancy concentration. Notably, the ceramics with x = 0.04 exhibit a high piezoelectric coefficient (d₃₃) of 37 pC·N⁻¹, excellent resistivity of 6.6×10⁶ Ω·cm at 500 °C, and a high Curie temperature of 681 °C. Piezoelectric force microscopy and phase field simulation reveal that the superior piezoelectric performance arises from larger domain sizes, a stronger response to external electric fields, and a higher breakdown field strength. These findings not only position this material as a robust candidate for high-temperature applications but also provide valuable insights into the design of piezoelectric ceramics with enhanced stability and performance.