Enhanced insulation and ferro/piezo-electric properties of BiFeO3–BaTiO3 via synchronous B-site co-doping and quenching treatment

Lead-free piezoelectric ceramics 0.7BiFe1-x(Zn0.5Sn0.5)xO3-0.3BaTiO3 [BF(ZS)x-BT] were successfully prepared using the solid-state reaction method. The dual effects of B-site Zn/Sn co-doping and quenching on the structure and piezoelectricity of BF(ZS)x-BT were investigated. All samples showed a distinct perovskite structure, characterized by the simultaneous presence of rhombohedral (R) and pseudo-cubic (pC) phases. The insulation and electrical properties were significantly increased by appropriate Zn/Sn co-doping and quenching treatment. The long parallel strip domains and enhanced lattice distortion synergistically contribute to the outstanding piezoelectricity (d33 = 203 pC/N) and a high Curie temperature (Tc = 493 °C) in quenched BF(ZS)0.003-BT. Furthermore, the quenching treatment was found to further improve the piezoelectric property and enhance its high-temperature stability, as demonstrated by the in-situ electromechanical coupling coefficient (kp) and thermal depolarization test. The d33 of the quenched BF(ZS)0.003-BT was maintained at 186 pC/N around 400 °C, highlighting its promising applications in medium-high temperature conditions.