Defect Dipole-Induced Fatigue Strain Recoverability in Lead-Free Piezoelectric Ceramics |
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Authors: | Binquan Wang Geng Huangfu Jie Wang Hua Li Yiping Guo |
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Affiliation: | State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240 China |
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Abstract: | Piezoelectric ceramics have garnered extensive utilization in high-precision actuators, where the magnitude of electric field-induced strain and fatigue resistance play crucial roles in actuation applications. Herein, an innovative strategy based on defect dipoles is proposed to form a defect-engineered polymorphic phase transition and achieve a giant piezoelectric strain coefficient of 3080 pm V−1 in Li/Sr-doped (K0.5Na0.5)NbO3 lead-free piezoceramics. The mechanism responsible for the enhanced strain performance lies in the optimized strain compatibility between the refined stripe domains and the nanosized domains. Additionally, the results demonstrate that the material is able to recover from fatigue-induced strain depletion under the stimulation of bipolar electric fields. This property can be phenomenologically explained by the rigid ion model, in which the application of reversal electric fields can facilitate the restoration of defect dipoles, thereby greatly contributing to strain recoverability. This study establishes a close correlation between the unipolar strain properties and the inherent flexibility of defect dipoles and provides new insight into the design of high-reliability, large-stroke piezoceramics. |
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Keywords: | defect dipoles domain configuration fatigue resistance giant electric field-induced strain lead-free piezoceramics |
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