Piezoceramics for high-power applications require both high piezoelectric coefficient (d33) and mechanical quality factor (Qm). However, the trade-off between them poses a significant challenge in achieving high values simultaneously, which is more prominent in lead-free piezoceramics. Here, we propose a new strategy, local Cu-acceptor defect dipoles embedded orthorhombic-tetragonal phase boundary engineering (O-T PBE), to balance d33 and Qm in potassium sodium niobate piezoceramics. This is validated in 0.95(K0.48Na0.52)NbO3-0.05(Bi0.5Na0.5)HfO3-0.2%molFe2O3-xmol%CuO ceramics. Our strategy simultaneously maintains the O-T PBE and introduces local dimeric <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41467_2025_58269_Article_IEq1.gif" Format="GIF" Height="22" Rendition="HTML" Resolution="72" Type="Linedraw" Width="105" /> </InlineMediaObject> <EquationSource Format="TEX">${({{Cu}}_{{Nb}}^{{\prime} {\prime} {\prime} }-{V}_{O}^{\bullet \bullet })}^{{\prime} }$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mrow> <mo>(</mo> <mrow> <msubsup> <mrow> <mi>C</mi> <mi>u</mi> </mrow> <mrow> <mi>N</mi> <mi>b</mi> </mrow> <mrow> <mo>″</mo> <mo>′</mo> </mrow> </msubsup> <mo>−</mo> <msubsup> <mrow> <mi>V</mi> </mrow> <mrow> <mi>O</mi> </mrow> <mrow> <mo>∙</mo> <mo>∙</mo> </mrow> </msubsup> </mrow> <mo>)</mo> </mrow> </mrow> <mrow> <mo>′</mo> </mrow> </msup> </math></EquationSource> </InlineEquation> and trimeric <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41467_2025_58269_Article_IEq2.gif" Format="GIF" Height="21" Rendition="HTML" Resolution="72" Type="Linedraw" Width="154" /> </InlineMediaObject> <EquationSource Format="TEX">${\left({V}_{O}^{\bullet \bullet }-{{Cu}}_{{Nb}}^{{\prime} {\prime} {\prime} }-{V}_{O}^{\bullet \bullet }\right)}^{\bullet }$</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mrow> <mfenced close=")" open="("> <mrow> <msubsup> <mrow> <mi>V</mi> </mrow> <mrow> <mi>O</mi> </mrow> <mrow> <mo>∙</mo> <mo>∙</mo> </mrow> </msubsup> <mo>−</mo> <msubsup> <mrow> <mi>C</mi> <mi>u</mi> </mrow> <mrow> <mi>N</mi> <mi>b</mi> </mrow> <mrow> <mo>″</mo> <mo>′</mo> </mrow> </msubsup> <mo>−</mo> <msubsup> <mrow> <mi>V</mi> </mrow> <mrow> <mi>O</mi> </mrow> <mrow> <mo>∙</mo> <mo>∙</mo> </mrow> </msubsup> </mrow> </mfenced> </mrow> <mrow> <mo>∙</mo> </mrow> </msup> </math></EquationSource> </InlineEquation> defects. The dimeric defects form defect dipole polarization that pins domain wall motion, while the trimeric ones introduce the local structural heterogeneity that leads to nano-scale multi-phase coexistence and abundant nano-domains. Encouragingly, for the Cu-doped sample with x = 1, Qm increases by a factor of 4, but d33 only decreases by 1/5 (i.e., achieving a d33 of 340 pC/N and a Qm of 256). Our research provides a new paradigm for balancing d33 and Qm in lead-free piezoceramics, which holds promise for high-power applications.

Excellent hardening effect in lead-free piezoceramics by embedding local Cu-doped defect dipoles in phase boundary engineering

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2025年3月25日

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Xinyue Qiu,
Chao Wu,
Daniel Q. Tan,
Ruihong Liang,
Chen Liu,
Yinchang Ma,
Xi-xiang Zhang,
Shiyang Wei,
Junwei Zhang,
Zhi Tan,
Zhipeng Wang,
Xiang Lv,
Jiagang Wu

摘要

Piezoceramics for high-power applications require both high piezoelectric coefficient (d₃₃) and mechanical quality factor (Q_m). However, the trade-off between them poses a significant challenge in achieving high values simultaneously, which is more prominent in lead-free piezoceramics. Here, we propose a new strategy, local Cu-acceptor defect dipoles embedded orthorhombic-tetragonal phase boundary engineering (O-T PBE), to balance d₃₃ and Q_m in potassium sodium niobate piezoceramics. This is validated in 0.95(K_0.48Na_0.52)NbO₃-0.05(Bi_0.5Na_0.5)HfO₃-0.2%molFe₂O₃-xmol%CuO ceramics. Our strategy simultaneously maintains the O-T PBE and introduces local dimeric ${({{Cu}}_{{Nb}}^{{\prime} {\prime} {\prime} }-{V}_{O}^{\bullet \bullet })}^{{\prime} }$ ${({C u}_{N b}^{″'} - V_{O}^{∙ ∙})}^{'}$ and trimeric ${\left({V}_{O}^{\bullet \bullet }-{{Cu}}_{{Nb}}^{{\prime} {\prime} {\prime} }-{V}_{O}^{\bullet \bullet }\right)}^{\bullet }$ ${(V_{O}^{∙ ∙} - {C u}_{N b}^{″'} - V_{O}^{∙ ∙})}^{∙}$ defects. The dimeric defects form defect dipole polarization that pins domain wall motion, while the trimeric ones introduce the local structural heterogeneity that leads to nano-scale multi-phase coexistence and abundant nano-domains. Encouragingly, for the Cu-doped sample with x = 1, Q_m increases by a factor of 4, but d₃₃ only decreases by 1/5 (i.e., achieving a d₃₃ of 340 pC/N and a Q_m of 256). Our research provides a new paradigm for balancing d₃₃ and Q_m in lead-free piezoceramics, which holds promise for high-power applications.