High-Performance Lead-Free Ceramics With Simultaneously High Piezoelectricity and High Mechanical Quality Factor.

Yang, Yang; Ying, Li; Wang, Dong; Wang, Zhipeng; Zhao, Jiantuo; Hao, Yanshuang; Ji, Yuanchao; Ren, Xiaobing · Adv Mater · 2025

basic_science · Level V

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Abstract

Piezoelectric materials with a high piezoelectric coefficient (d<sub>33</sub>) and high mechanical quality factor (Q<sub>m</sub>) are vital for advanced high-power applications. However, achieving this combination is challenging, particularly for lead-free piezoelectrics, because a high d<sub>33</sub> value relies on mobile domain walls, which increase dissipative losses and reduce Q<sub>m</sub>. In this study, this longstanding trade-off is overcome by introducing defect dipoles (via Mn doping) into the quadruple point (QP) composition of the lead-free Ba(Sn, Ti)O<sub>3</sub> system. The resultant 0.5%Mn-doped Ba(Sn<sub>0.11</sub>Ti<sub>0.89</sub>)O<sub>3</sub> (BST-0.5%Mn) ceramic exhibits a high d<sub>33</sub> value of 710 pC/N and high Q<sub>m</sub> value of 929, while the BST-1%Mn ceramic achieves a d<sub>33</sub> value of 614 pC/N and Q<sub>m</sub> value of 1138. These values represent a 10-fold increase in Q<sub>m</sub> and 1.6-fold increase in d<sub>33</sub> for BST-0.5%Mn, compared to those for undoped BST. High-resolution scanning transmission electron microscopy and phase-field simulations reveal that the enhanced d<sub>33</sub> and Q<sub>m</sub> are attributable to the coexistence of multiple phases of QPs with symmetry-conforming defect dipoles, challenging the long-held notion of physical incompatibility between high d<sub>33</sub> and high Q<sub>m</sub>. These findings offer a pathway for designing eco-friendly piezoelectric materials with unprecedented performance, paving the way for sustainable and efficient high-power applications.