Simultaneous enhancement of electrical and mechanical properties in CaBi2Nb2O9-based ceramics

CaBi2Nb2O9 (CBN) with Aurivillius phase has an enormous potential in high-temperature piezoelectric devices due to their high Curie temperature and excellent free-fatigue characteristics. Nevertheless, simultaneous enhancement of electrical and mechanical properties in CBN-based ceramics are still a great challenge because of the trade-off between the electrical and mechanical properties. Herein, a strategy, the synergy effect of lattice distortion and oxygen vacancy, is designed to realize the enhanced electrical and mechanical properties of CBN-based ceramics via the domain structure and grain size engineering. The materials can simultaneously deliver a high piezoelectric property of 17.3 pC/N, large hardness of 4.68 GPa, and intensive bending strength of 113.07 MPa, which are enhanced by 346%, 197%, and 141% over those of unmodified CBN ceramics. We believe that the founding of this research opened up a novel and efficient guideline for exploring new bismuth-layered structure ceramics with excellent electrical and mechanical properties.