High Piezoelectricity and Temperature Stability via Stabilized Polar Distortion

Simultaneously combining high piezoelectric performance with excellent thermal stability is essential for piezoelectrics operating under high-temperature conditions, yet these two attributes are often in competition. Here, we propose a design strategy that stabilizes the intrinsic lattice contribution by constructing a mixed-symmetry ferroelectrically distorted state and demonstrate its effectiveness in Pb(Zr_0.53Ti_0.47)O₃-xNb (Nx) ceramics. The optimized N3 composition exhibits a high piezoelectric coefficient d₃₃ of 550 pC/N and a high Curie temperature T_C of 367°C. Over the wide temperature range of 25-300°C, the variations in piezoelectric coefficient (d₃₃) and electromechanical coupling factor (k_p) are limited to only 6% and 9%, respectively. In situ temperature-dependent structural analyses reveal that the enhanced piezoelectricity and thermal robustness originate from a ferroelectric distortion that is strongly developed at room temperature due to niobium doping and remains stable up to 300°C, as further corroborated by first-principles calculations and scanning probe microscopy measurements. This mixed-symmetry-stabilization strategy provides a generalizable route to overcoming the conventional trade-off between performance and stability and offers design guidelines for next-generation high-performance piezoceramics tailored for high-temperature applications.