It was reported that a tetragonal phase can be stabilized with maintaining good piezoelectric properties when Na0.5K0.5NbO3 (KNN) is modified with 0.06 mol SrTiO3. However, such a high amount of SrTiO3 leads not only to poor sinterability but low Curie temperature (TC). To maintain high TC with good piezoelectric properties in KNN-based lead-free piezoelectric ceramics, this study investigates the effect of Li-doping on the dielectric and piezoelectric properties of 0.96Na0.5K0.5NbO3-0.04SrTiO3 (KNN-4ST) ceramics. As a result, the orthorhombic-tetragonal phase transition was observed at 2 mol% Li2CO3 modified KNN-4ST ceramics, whose TC, d33 and kp values are 328℃, 165pC/N and 0.33, respectively.
