Significantly enhancing high-temperature piezoelectric response and Tdr of BF-BT-based ceramics through multi-component optimization strategy

Phase boundary-domain engineering modulation with diverse group elements and coexistence of multiphase and composite domain structures is a good pathway that can be realized to simultaneously improve the piezoelectric properties of BF-BT ceramics and their thermal stability. Here, we propose a multicomponent optimization strategy. We innovatively introduce the 0.8(Bi0.5Na0.5)TiO3-0.2(Bi0.5K0.5)TiO3 (BNT-20BKT) component to 0.69BF-0.31BT ceramic, to build a morphotropic phase boundary (MPB) for enhancing d(33). Meanwhile, Bi(Zn0.5Ti0.5)O-3 with high Curie temperature and high tetragonal degree was introduced with the expectation of obtaining higher thermal stability along with high piezoelectric properties. The 0.69BiFeO(3)-0.31BaTiO(3)-0.005[0.8(Bi0.5Na0.5)TiO3-0.2(Bi0.5K0.5)TiO3]-xBi(Zn0.5Ti0.5)O-3 (referred to as BF31BT-0.005(BNT-20BKT)-xBZT, 0.00 <= x <= 0.025) ceramics were successfully prepared. For the first time, an ultra-high piezoelectric performance of 749.6 pC/N was achieved at a real-time depolarization temperature (T-dr) of 395.6 degrees C, reflecting the real-time piezoelectric properties and ultra-high temperature stability of the ceramic at high temperatures. A two-phase coexisting structure of R and PC phases was produced in BF31BT-0.005(BNT-20BKT)-0.025BZT ceramic. TEM results showed the formation of nanodomains and a large number of polar nanoregions (PNRs). By adjusting the appropriate R/PC phase ratio, oxygen octahedral distortion, and optimizing the local domain engineering, an effective strategy is provided for simultaneously achieving ultra-high temperature stability and ultra-high piezoelectric response.