Giant d 33 in (K,Na)(Nb,Sb)O3-(Bi,Na,K, Li)ZrO3 based lead-free piezoelectrics with high T c

In this work, a lead-free piezoelectric system based on (1−x)(K0.48Na0.52)(Nb0.95Sb0.05)O3-xBi0.5(Na0.7K0.2Li0.1)0.5ZrO3 [(1−x)KNNS-xBNKLZ] is developed, and a rhombohedral-tetragonal phase boundary is constructed in this system. The relationship between the phase boundary and the piezoelectric properties of the (1−x)KNNS-xBNKLZ ceramics is illuminated. The coexistence of a tetragonal phase and a rhombohedral phase is identified in the composition range of 0.03 < x < 0.05. For such composition, the ceramics show giant d33 of ∼380 pC/N, high Tc of ∼290 °C, and a good thermal-depolarization behavior (d33 > 300 pC/N) of ∼210 °C. We believe that the (1−x)KNNS-xBNKLZ system is very promising for lead-free piezoelectric applications.