Energy storage density and piezoelectric performances of barium strontium titanate modified bimuth sodium lanthanum titanate lead-free ceramics

Abstract

Lead-free (1-x)(Bi0.487Na0.487La0.017)TiO3-x(Ba0.7Sr0.3)TiO3 or (1-x)BNLT-xBSrT ceramics were fabricated by a solid state reaction and sintered at 1050–1200 °C for 2 h. All sintered samples had a relative density > 97% of their theoretical values. With increasing BSrT, the transition from BNLT rhombohedral to BSrT tetragonal was observed. The addition of BSrT inhibited grain growth which resulted in the improvement of the densification of the BNLT ceramic. The changes in the BSrT content also induced a phase transition from the ferroelectric (FE) phase to the ergodic relaxor (ER) phase. These changes significantly disrupted long-range ferroelectric order, thereby correspondingly reducing the Pr and Ec values and resulting in the enhancement of the electric field-induced strain and electrostrictive response. A large Smax = 0.41%, d*33 = 788 pm/V and electrostrictive coefficient (Q33 = 0.04119 m4/C2) were observed for the x = 0.08 sample. In addition, the x = 0.15 sample showed good energy storage density (W = 0.66 J/cm3) and energy storage efficiency (η = 82.7%) @ 150 °C. Overall, these results indicated that these ceramics had the potential of becoming one of the promising lead-free piezoelectric candidates for piezoelectric applications.