Textured Potassium Sodium Niobate Lead-Free Ceramics with High d 33 and Q m for Meeting High-Power Applications.

Potassium sodium niobate (KNN) lead-free piezoceramics have garnered significant attention for their environmentally friendly attributes, desired piezoelectric activity ( d ₃₃ ), and high Curie temperature ( T _c ). However, the limited applicability of most KNN systems in high-power apparatus, including ultrasonic motors, transformers, and resonators, persists due to the inherent low mechanical quality factor ( Q _m ). Herein, we proposed an innovative strategy for achieving high Q _m accompanied by desirable d ₃₃ via synergistic chemical doping and texturing in KNN piezoceramics. Comprehensive electrical measurements along with quantitative structural characterization at multilength scales reveal that the excellent electromechanical properties ( k _p = 0.58, d ₃₃ ∼ 134 pC·N ^-1 , Q _m = 582, and T _c ∼ 415 °C) originate from the high <001> texturing degree, nanodomain, as well as acceptor hardening. Our findings provide an insight and guidance for achieving high-power performance in lead-free KNN-based piezoceramics, which were expected to be used in advanced transducer technology.