Achieving Large Piezoelectricity in Bismuth Titanate Niobate-Based High-Temperature Ceramics with Scandium Substitution

The industry has recently expressed an eager demand for piezoelectric materials capable of sensing pressure, acoustics, and vibrations at high temperatures. For high-temperature piezoelectric materials, it is generally incompatible to achieve a high Curie temperature and large piezoelectricity. Herein, we meticulously dope the scandium into the Bi2.96Ce0.04TiNbO9 ceramic to address this dilemma. The doping of scandium causes the oxygen octahedron to rotate and tilt along the direction of spontaneous polarization, enhancing the intrinsic contribution of piezoelectricity. The increased domain size coupled with the facilitated domain rotation leads to an improved extrinsic contribution. Moreover, the scandium doping can improve the resistivity by refining grains and forming defect dipoles to reduce the concentration of oxygen vacancies. The BCTN-2Sc ceramic exhibits excellent electrical comprehensive properties: large piezoelectricity (19.2 pC/N), high Curie temperature (915 °C), large resistivity (6.4 × 105 Ω·cm @600 °C), and superior thermal stability, which make it a promising candidate for high-temperature sensing applications.