Role of ZnO dopant in enhancing piezoelectric characteristics in KNN‐based piezoelectric ceramics

Abstract Considering that lead‐based piezoelectric ceramics are not conducive to sustainable development, the research and preparation of environmentally friendly lead‐free piezoelectric ceramics has become a new trend. Among them, potassium‐sodium niobate based (KNN‐based) piezoelectric ceramics are considered as the most potential candidates because of their good piezoelectric properties. However, the strong sensitivity to temperature has hindered the further application of KNN‐based ceramics. In this work, the ZnO dopant was introduced in 0.96K 0.48 Na 0.52 Nb 0.96 Sb 0.04 O 3 –0.04Bi 0.5 Na 0.5 HfO 3 ceramics to improve their piezoelectric characteristics. On the one hand, Zn 2+ could occupy B‐site and thus enhance the lattice distortion of BO 6 octahedra, resulting the enhanced piezoelectric properties including k p = 46%, d 33 = 344 pC/N and T C = 282°C in the optimal component with x = 0.01. On the other hand, the defect dipole formed by the acceptor dopant Zn 2+ pinned the motion of domain wall, and thus improved the temperature stability over a wide temperature range of 20°C to 180°C, where the descent in unipolar strain decreased from 35% ( x = 0) to 23% ( x = 0.01). This work provides a point of view about how ZnO dopants make an influence on the KNN‐based ceramics.