Phase structure, electrical properties, and stability of 0.96(K0.48Na0.52)1−xLixNbO3–0.04Bi0.5Na0.5ZrO3 lead-free piezoceramics

• Both a high TC and an enhanced d33 are attained in KNNLix–BNZ ceramics.
• Adding Li could result in the increase of TC and the decrease of TO–T.
• An orthogonal–tetragonal phase structure is observed with x = 0.02.
• d33 ∼ 255 pC/N, kp ∼ 41%, and a high TC of ∼360 °C were observed.

In this work, 0.96(K0.48Na0.52)1−xLixNbO3–0.04Bi0.5Na0.5ZrO3 lead-free piezoceramics were prepared using the conventional solid state reaction method in order to attain both a high TC and an enhanced d33. The effect of Li content on their phase structure, electrical properties, and stability was systematically investigated. These results indicate that adding Li could result in the increase of TC and the decrease of TO–T. Here we obtain the ceramics with an orthogonal–tetragonal phase boundary in the composition of x = 0.02, and then enhanced piezoelectric properties and a high Curie temperature (i.e., d33 ∼ 255 pC/N, kp ∼ 41%, and TC ∼ 360 °C) were observed, showing the realization of our objective. In addition, a good stability of piezoelectric and ferroelectric properties has been shown in such a material system.