Synergistic enhancement of electrical properties and thermal stability in CaBi2Nb2O9 piezoceramic through A-site doping and grain refinement engineering

CaBi 2 Nb 2 O 9 (CBN) piezoceramics have been extensively studied due to their high Curie temperature, which enables them to maintain functionality at elevated temperatures. However, achieving both high piezoelectric performance and resistivity at temperatures exceeding 500 °C remains a critical challenge. Through Li/Ce co-doping and grain engineering, we have synthesized Ca 0.88 (Li 0.5 Ce 0.5 ) 0.12 Bi 2 Nb 2 O 9 ceramic, which exhibits optimal performance with a piezoelectric coefficient d 33 of 17.0 pC/N, a very high Curie temperature of 921 °C, and a high-temperature resistivity of 1.2 × 10 6  Ω cm at 550 °C. Microstructural analysis reveals that grain refinement plays a pivotal role in optimizing the properties of the CBN piezoceramics.