Ultrahigh piezoelectric performances of (K,Na)NbO<sub>3</sub> based ceramics enabled by structural flexibility and grain orientation.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39837848.
- Also identified by DOI 10.1038/s41467-025-56074-8 and PMC identifier 11751466.
- Licence recorded as CC BY-NC-ND.
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Abstract
(K,Na)NbO<sub>3</sub>-based ceramics are deemed among the most promising lead-free piezoelectric materials, though their overall piezoelectric performance still lags behind the mainstream lead-containing counterparts. Here, we achieve an ultrahigh piezoelectric charge coefficient d<sub>33</sub> ∼ 807 pC·N<sup>-1</sup>, along with a high longitudinal electromechanical coupling factor (k<sub>33</sub> ∼ 88%) and Curie temperature (T<sub>c</sub> ∼ 245 °C) in the (K,Na)(Nb<sub>1-x</sub>Sb<sub>x</sub>)O<sub>3</sub>-Bi<sub>0.5</sub>Na<sub>0.5</sub>ZrO<sub>3</sub>-BiFeO<sub>3</sub> (KNN-xSb) system through structural flexibility and grain orientation strategies. Phenomenological models, phase field simulations and high-angle annular dark-field scanning transmission electron microscopy reveal that the structural flexibility originates from the high Coulomb force between K<sup>+</sup>/Na<sup>+</sup> ions and Sb ions in the KNN-xSb system, while the grain orientation promotes the displacement of B-site cations leveraging the engineered domain configuration. As a result of its excellent comprehensive piezoelectric properties, the textured KNN-5Sb/epoxy 1-3 piezoelectric composite is found to possess a broader bandwidth BW = 60% and higher amplitude output voltage than commercial PZT-5 and other KNN counterparts. These findings suggest that the textured KNN-5Sb ceramics could potentially replace current lead-based piezoceramics in transducer applications.