Microstructure and electrical properties of relaxor (1 − x)[(K0.5Na0.5)0.95Li0.05](Nb0.95Sb0.05)O3–xBaTiO3 piezoelectric ceramics

In order to solve the low temperature stability of electrical properties in KNN-based ceramics, (1 − x)[(K0.5Na0.5)0.95Li0.05](Nb0.95Sb0.05)O3–xBaTiO3 [(1 − x)KNLNS–xBT] lead-free piezoelectric ceramics were prepared by the conventional solid-state sintering method. The introduction of BT stabilizes the tetragonal phase of KNLNS ceramics at room temperature, results in a typical ferroelectric relaxor behavior, and shifts the polymorphic phase transition to below room temperature. Moreover, there is a strong BaTiO3 concentration dependence of relaxor behavior and electrical properties, and the ceramic with x = 0.005 exhibits optimum electrical properties and typical relaxor behavior (d33 = 269 pC/N, kp = 0.50, ɛr = 1371, tan δ = 0.03, TC ∼ 349 °C and γ = 1.88024). These results indicate that the BT is an effective way to improve the temperature stability as well as the electrical properties of KNN-based ceramics.