In recent years, the rapid development of advanced technologies such as aerospace, deep-well exploration, and nuclear energy systems has created a growing demand for piezoelectric materials capable of operating in high-temperature environments (>500 °C). Bismuth layer-structured ferroelectrics (BLSFs) have become promising candidates for high-temperature piezoelectric applications owing to their intrinsically high Curie temperatures, good thermal stability, and excellent fatigue resistance. Among various BLSF compounds, CaBi 4 Ti 4 O 15 (CBT) is a highly attractive system because of its high Curie temperature of approximately 790 °C. However, the volatilization of bismuth during sintering of CBT generates oxygen vacancy defects, which pin domain walls. Meanwhile, the spontaneous polarization of bismuth layer-structured materials is confined to the a – b plane. These factors lead to a relatively low piezoelectric coefficient ( d 33 ) of CBT, thus limiting its practical applications.
Researchers led by Yejing Dai and Bin Li at Sun Yat-sen University have investigated donor–acceptor aliovalent co-doping in CBT ceramics. By introducing Cr3+ and Ta5+ at the Ti sites, they obtained an optimized composition, CaBi 4 Ti 3.96 (Cr 1/3 Ta 2/3 ) 0.04 O 15 , that combines an enhanced piezoelectric response with a high Curie temperature.
The study links the improved response to the combined effects of local structural changes, oxygen-vacancy regulation, and domain configuration. The ceramics were prepared by a conventional solid-state reaction method, providing a practical approach for further investigation of high-temperature piezoelectric materials.
The study is published in Journal of Advanced Ceramics on October 12, 2026.
In this work, Ta 5+ acts as a donor and Cr 3+ as an acceptor when substituting for Ti4+. X-ray diffraction and Raman measurements support dopant incorporation and changes in the local lattice environment that may enhance the intrinsic polarization contribution. X-ray photoelectron spectroscopy, electron paramagnetic resonance, and leakage-current measurements together indicate fewer oxygen-vacancy-related defects at the optimized doping level. Reduced defect pinning, together with the formation of high-density stripe domains and larger plate-like grains, is proposed to facilitate domain responses. Piezoresponse force microscopy (PFM) reveals a stronger local electromechanical response in the optimized ceramic, while switching spectroscopy PFM results reported in the paper support enhanced field-induced domain switchability. The proposed defect-chemistry model further suggests that Cr-related acceptor defects associate with residual oxygen vacancies, limiting their long-range migration. The optimized ceramic has a room-temperature d 33 of 25.7 pC/N, a Curie temperature of 792 °C, and a DC resistivity of 9.5×10 6 Ω·cm at 500 ° C. After annealing at 600 °C for 1 h and cooling to room temperature, its d 33 is 23.3 pC/N, a decrease of only 9.4% from the initial value. In a separate cycling test, the sample was repeatedly heated to 500 °C, held for 1 h, and cooled to room temperature before measurement. Following an initial decrease, d 33 remained at approximately 25.2 pC/N over the subsequent cycles. These measurements demonstrate resistance to thermal depolarization under the tested conditions; they measure piezoelectric retention after cooling. Compared with representative modified CBT ceramics reported in the literature, the composition offers a competitive d 33 while preserving the high Curie temperature of the parent material.
Other contributors include Junhui Tan, Xuanyu Chen, Yuxing Dai, Yi Cheng, Xiqi Chen, Bao Ou, and Guanfu Liu, all from the School of Materials, Shenzhen Campus of Sun Yat-sen University, China.
About the Authors
Yejing Dai received her Ph.D. from Tsinghua University. She is currently a Professor, Doctoral Supervisor, and Yat-sen Outstanding Scholar at the School of Materials, Sun Yat-sen University. Her research focuses on lead-free piezoelectric ceramics, defect dipoles, and piezotronics/piezo-photonics.
Bin Li received his Ph.D. from the National University of Defense Technology. He is currently a Professor, Doctoral Supervisor, and Yat-sen Distinguished Scholar at the School of Materials, Sun Yat-sen University. His research mainly focuses on aerospace composite materials and intelligent sensing materials.
Funding
This work was supported by the National Natural Science Foundation of China (52172135), the Youth Top Talent Project of the National Special Support Program (2021-527-07), the Leading Talent Project of the National Special Support Program (2022WRLJ003), and the Shenzhen Science and Technology Program (JCYJ20240813151421028).
DOI LINK: 10.26599/JAC.2026.9221394
About Journal of Advanced Ceramics
Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen . JAC’s 2025 IF is 14, ranking in Top 1 (1/34, Q1) among all journals in “Materials Science, Ceramics” category, and its 2025 CiteScore is 24.6 (6/133) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508
Journal of Advanced Ceramics
Defect engineering of oxygen vacancies and domain configuration for high-performance CaBi4Ti4O15 piezoelectric ceramics
12-Oct-2026