Enhanced electric-field-induced strains in (K,Na)NbO3 piezoelectrics from heterogeneous structures

Mao Hua Zhang, Qinghua Zhang, Ting Ting Yu, Geng Li, Hao Cheng Thong, Li Ying Peng, Lisha Liu, Jing Ma, Yang Shen, Zhijian Shen, John Daniels, Lin Gu, Bing Han, Long Qing Chen, Jing Feng Li, Fei Li, Ke Wang

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Piezoelectrics exhibit mechanical strain in response to electrical stimuli and vice versa. A high level of electric-field-induced strain with minimal hysteresis is desired for piezoelectric materials when used as actuators. The past two decades have seen extensive research into lead-free piezoelectrics to replace Pb(Zr,Ti)O3 and compositional engineering has been demonstrated to be an effective method to tailor their functional properties. Doped (K,Na)NbO3 (KNN) compositions with elaborate compositional tuning can exhibit enhanced electromechanical properties. However, a balance between enhanced properties and non-toxicity of the dopants should be considered. In this work, we propose to use microstructural engineering to enhance the properties. Based on phase-field simulations, we propose to take advantage of depolarization energies generated by polar-nonpolar interfaces, to increase the contribution of domain wall motion to electric-field-induced strain. Heterogeneous ferroelectric-paraelectric microstructures were introduced into a KNN ceramic via a two-step sintering process. Their presence was characterized by high-resolution transmission electron microscopy. Enhanced reversible domain wall motion was verified by in situ high-energy X-ray diffraction. Electric-field-induced strain is enhanced by 62% and 200% at 25 °C and 150 °C, respectively. Considering lead-free piezoelectrics also represent an emerging class of biomaterials for medical technology, the non-toxicity and biocompatibility of the investigated compositions are examined by in vitro cell viability assays.

Original languageEnglish (US)
Pages (from-to)44-53
Number of pages10
JournalMaterials Today
StatePublished - Jun 2021

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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