Effect of BiFeO3 additions on the dielectric and piezoelectric properties of (K0.44Na0.52Li0.04)(Nb0.84Ta0.1Sb0.06)O3 ceramics

(1 − x) (K0.44Na0.52Li0.04)(Nb0.84Ta0.1Sb0.06)O3 − x BiFeO3 (x = 0, 0.002, 0.004, 0.006, 0.008, 0.01) lead-free piezoelectric ceramics were prepared by the conventional ceramic processing. The compositional dependence of the phase structure and the electrical properties of the ceramics were studied. A morphotropic phase boundary between the orthorhombic and tetragonal phases was identified in the composition range of 0.004 < x < 0.006. The ceramics near the morphotropic phase boundary exhibit a strong compositional dependence and enhanced piezoelectric properties. The ceramics with 0.6 mol.% BiFeO3 exhibit good electrical properties (d33 ∼ 246 pC/N, kp ∼ 43%, Tc ∼ 285 °C, ɛr ∼ 1871, and tan δ ∼ 1.96%). These results show that the (1 − x) (K0.44Na0.52Li0.04)(Nb0.84Ta0.1Sb0.06)O3 − x BiFeO3 ceramic is a promising lead-free piezoelectric material for applications in different devices.