Superior Piezoelectricity in Bismuth Titanate‐Based Lead‐Free High‐Temperature Piezoceramics via Domain Engineering

Abstract High‐temperature piezoelectric materials are widely needed in electromechanical sensors, actuators, and transducers that are exposed to high‐temperature conditions. Bismuth layer‐structured bismuth titanate (Bi 4 Ti 3 O 12 , BIT) ferroelectrics have a high Curie temperature of 675 °C but suffer from poor electrical properties, especially the piezoelectricity. Here, a giant piezoelectric coefficient d 33 of 40.2 pC N −1 is obtained in the Bi 3.97 Ce 0.03 Ti 2.98 (WNb) 0.01 O 12 ceramics with a high Curie temperature of 657 °C, the highest value reported to date in BIT‐based piezoceramics. Electrical property and microstructural analysis reveal that the high piezoelectricity benefits from the preferential orientation of ferroelectric domains, the irreversibility of ferroelectric domain reorientation, and the high density of ferroelectric domain walls. Besides, excellent thermal stability of piezoelectric constant ( d 33 = 36.7 pC N −1 at 500 °C, <10% variations in the range of room temperature to 500 °C), high electrical resistivity (ρ > 10 7 Ω cm at 500 °C), and low loss (tanδ < 1.5% at 500 °C) are also obtained in the Bi 3.97 Ce 0.03 Ti 2.98 (WNb) 0.01 O 12 ceramics. This work not only penetrates the origins of outstanding piezoelectricity of BIT‐based ceramics but also offers prospects for brand‐new tactics to exploit high‐performance high‐temperature piezoceramics.