TY  - JOUR
AU  - Zhang, Feng
AU  - Yang, Yaodong
AU  - Li, Jianting
AU  - Zhang, Xiancheng
AU  - Li, Junjie
AU  - Tang, Yimeng
AU  - Qu, Shuo
AU  - Bai, Yang
AU  - Rao, Wei-Feng
PY  - 2026
TI  - Ultrahigh electrostrain with exceptional temperature stability in BNT-based ceramics via synergistic regulation of critical phase and domain engineering
JO  - Journal of Advanced Ceramics
SN  - 2226-4108
SP  - 9221196
VL  - 15
IS  - 1
AB  - 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.
UR  - https://doi.org/10.26599/JAC.2025.9221196
DO  - 10.26599/JAC.2025.9221196