Low electric field-induced strain and large improvement in energy density of (Lu0.5Nb0.5)4+ complex-ions doped BNT–BT ceramics

The (Bi0.5Na0.5)0.94Ba0.06Ti(1 − x)(Lu0.5Nb0.5)xO3 (BNBT–xLN, x = 0, 0.02, 0.03, 0.04, 0.05, 0.07) ceramics were designed to investigate their dielectric, ferroelectric, energy storage and electrostriction properties. All ceramics illustrated single pseudo-cubic perovskite structure and densely stacked microstructure. The LN doping disturbed the long-range ordered ferroelectric phase, which was confirmed by the depressed P–I–E loops and S–E curves. The excellent piezoelectric response was realized in the coexistence region of the ferroelectric polar and weak-polar phases. A significant enhancement of electric field-induced strains (Smax = 0.42%) with a large average normalized strain coefficient (d33* = Smax/Emax) of 602.41 pm/V, electrostriction coefficient (Q33 = 0.0334 m4/C2) was achieved at x = 0.02. And a high energy storage density of 0.72 J/cm3 was obtained at x = 0.03. As a result, the systematic investigations on the BNBT–xLN ceramics can benefit the developments of low electric field piezoelectric and energy storage devices.