Ultrahigh electrostrain with excellent fatigue resistance in textured Nb ⁵⁺-doped (Bi _0.5Na _0.5)TiO ₃-based piezoceramics

(Bi0.5Na0.5)TiO3 (BNT)-based lead-free piezoceramics exhibit excellent electric field-induced strain (electrostrain) properties, but often suffer from large hysteresis and poor fatigue resistance, which strongly limit their applications. Here, <00l> textured Nb5+-doped 0.8(Bi0.5Na0.5)TiO3–0.2(Bi0.5K0.5)TiO3 (0.8BNT–0.2BKT) ceramics with a high degree of texturing (~80%) were prepared by the reactive template grain growth (RTGG) method using Bi4Ti3O12 as template. By combination donor doping in B-site RTGG method, electrostrain performance achieves significant enhancement. A 0.65% piezoelectric coefficient ( d33*) 1083 pm/V reduced at an field 6 kV/mm are obtained. No degradation is observed after unipolar loading 105 cycles, showing endurance. These results indicate that BNT-based useful approach to developing eco-friendly actuators.