Excellent thermal-cycling stability caused by aging in Fe-doped (Ba_0.85Ca_0.15)(Ti_0.9Zr_0.1)O₃ lead-free piezoceramic

A key challenge for the practical application of lead-free piezoelectrics is how to acquire high-piezoelectricity and good thermal-cycling stability simultaneously. Here, we report that excellent thermal-cycling stability was obtained in aged (Ba_0.85Ca_0.15)(Ti_0.9Zr_0.1)_99.75/100Fe_0.25/100O_3-δ lead-free piezoceramic with high-piezoelectricity (d₃₃ ~ 400 pC/N). No piezoelectricity degradation was found for the aged sample after 100 thermal cycles between -40 °C and 50 °C. Further studies on hysteresis loop and evolution of microstructures reveal that the excellent thermal-cycling stability is related to the point-defect migration during aging. This work indicates that aging is an effective way to obtain good thermal-cycling stability and high-piezoelectricity simultaneously.