Phase transition and electrical properties of (1 − x)K0.02Na0.98NbO3-xBaTiO3 ceramics

► Lead-free piezoelectric ceramics (1 − x)K0.02Na0.98NbO3-xBaTiO3 with good piezoelectric properties were obtained. ► The crystal structures of (1 − x)K0.02Na0.98NbO3-xBaTiO3 ceramics change from monoclinic to orthorhombic, and then to tetragonal, with an increase in BaTiO3 content. ► The 0.9K0.02Na0.98NbO3-0.1BaTiO3 ceramics have high d33 (160 pC/N) with low ferroelectric-ferroelectric transition temperature (−15 °C).