Boosting comprehensive electrical properties of CaBi4Ti4O15 ceramics by multi-ion doping for high-temperature piezoelectric sensor applications

Structural tuning and composition optimization are key factors in enhancing the piezoelectric response of Aurivillius-phase bismuth layer-structured ceramics. In this work, a multi-ion doping strategy involving Ce4+, Mo6+, and Ga3+ was designed to optimize the crystal and domain structures of CaBi4Ti4O15 ceramics (CCBT-MGx, x = 0.00-0.10), leading to significant improvements in their piezoelectric properties. The joint analysis results of Raman spectroscopy, transmission electron microscope (TEM), and piezoelectric force microscope (PFM) indicate that the optimized CCBT-MG0.06 ceramics exhibits greater distortion of [TiO6] octahedron and a more easily oriented domain structure. As a result, CCBT-MG0.06 ceramics achieve a three times piezoelectric constant (d33 = 24.7 pC/N) that of pure CaBi4Ti4O15 ceramics (d33 = 8 pC/N). In addition, CCBT-MG0.06 ceramics also exhibits excellent other electrical properties and stability: the Curie temperature TC reaches 773.3 degrees C, the DC resistivity exceeds 107 Omega center dot cm with a low dielectric loss of only 4.3 % at 500 degrees C, and the d33 value remains 23.6 pC/N after annealing at 500 degrees C. This work provides a highly effective strategy for developing bismuth layer-structured ceramics with superior comprehensive electrical properties that meet the requirements of high-temperature piezoelectric sensor applications.