@article{Zhang2026, 
author = {Feng Zhang and Yaodong Yang and Jianting Li and Xiancheng Zhang and Junjie Li and Yimeng Tang and Shuo Qu and Yang Bai and Wei-Feng Rao},
title = {Ultrahigh electrostrain with exceptional temperature stability in BNT-based ceramics via synergistic regulation of critical phase and domain engineering},
year = {2026},
journal = {Journal of Advanced Ceramics},
volume = {15},
number = {1},
pages = {9221196},
keywords = {temperature stability, domain structure, bismuth sodium titanate (BNT), strain response, relaxor state, phase boundary.},
url = {https://www.sciopen.com/article/10.26599/JAC.2025.9221196},
doi = {10.26599/JAC.2025.9221196},
abstract = {Bismuth sodium titanate-based (Bi0.5Na0.5TiO3, BNT) lead-free piezoelectric ceramics exhibit significant potential for precision actuation because of their large electrostrain. However, the inherent trade-off between high electrostrain performance and temperature stability hinders their practical application. This study addresses this challenge by developing a series of Bi0.47Na0.47Ba0.06Ti1−xHfxO3 (BNBT-100xH) ceramics via a B-site Hf4+ doping strategy enabling synergistic regulation of the phase boundary and domain state. The optimized BNBT-3H composition (x = 0.03) features a morphotropic phase boundary (MPB) comprising coexisting rhombohedral (R3c, 51%) and tetragonal (P4bm, 49%) phases, alongside a unique coexistence domain structure of ferroelectric macrodomains and relaxor nanodomains (~100 nm). This microstructural design achieves an ultrahigh bipolar electrostrain of up to 0.6% (d33* = 500 pm/V), along with an ultralow temperature fluctuation of only 16.7% over a wide temperature range of 25–150 °C. Notably, the electrostrain at 150 °C decreases by only 4% compared with that at room temperature, demonstrating excellent thermal stability and overall performance superior to those of other lead-free systems. Through multiscale characterization, the origin of the high electrostrain is confirmed to stem from an electric field-induced reversible relaxor–ferroelectric phase transition, facilitated by the flattened energy landscape at the critical rhombohedral–tetragonal phase boundary. Simultaneously, the exceptional thermal stability arises from the thermal-electric driven dynamic equilibrium within the multiphase nanodomain structure. This work not only provides a high-performance material candidate for broad-temperature-range precision actuators but also offers novel insights into optimizing functional ceramics through precise microstructure control.}
}