Significantly enhanced piezoelectric temperature stability of KNN-based ceramics through multilayer textured thick films composite

The temperature instability of piezoelectric properties in KNN-based ceramics has been a major bottleneck impeding them toward practical applications. Herein, we prepared multilayer composite ceramics using two kinds of textured thick films with different polymorphic phase transition temperatures. The composite ceramics simultaneously exhibited outstanding piezoelectric properties (d 33 = 400 ± 20 pC/N; S = 0.18 % at 40 kV/cm) and piezoelectric temperature stability (d 33 and S variation within 5 % and 2 %, respectively over the temperature range of room temperature to 180 °C). The synergistic contribution of slightly fluctuating ε r ·P r values, the robust phase and domain structures, and the complementary effect of piezoelectric fluctuation between the two composite layers led to the outstanding temperature stability of piezoelectric properties . Furthermore, the piezoelectric energy harvester produced using KNN-T 1 /T 2 composite ceramics exhibits a large power density of 5.4 mW/cm 3 . These results prove great potential of KNN-T 1 /T 2 ceramics in high temperature piezoelectric devices.