In the search for lead-free piezoceramics candidates, alkali
niobate ceramics based on (K0.5Na0.5)NbO3 (KNN) have received
more attention since Saito et al. [1] made a breakthrough in
the textured KNN ceramics with codopants of Li, Ta, and Sb,
which showed comparable piezoelectric properties to a hard
Pb(Zr,Ti)O3 (PZT). However, it is difficult to prepare dense KNN
ceramics due to the volatility of alkaline elements during sintering
process. Therefore, many attempts have been made toward
solving the above-mentioned issues such as the formation of solid
solutions of KNN with other ferroelectrics or nonferroelectrics
[5–7] and the use of sintering aids [8,9]. Among these new solid
solutions, (K0.5Na0.5)NbO3–LiSbO3 [10–13] system seems more
interesting as it reveals excellent piezoelectric properties and
high Curie temperature Tc. Zhang et al. [13] demonstrated that
the 0.948 K0.5Na0.5NbO3–0.052LiSbO3 (KNNLS) ceramics exhibited
good electrical properties (d33 = 265 pC/N and Tc = 368 ◦C). Nevertheless,
the properties near room temperature are strongly
temperature dependent due to the presence of the orthorhombic
to tetragonal polymorphic phase transition [13]. Furthermore, the
fairly low mechanical quality factor (Qm = 40) [13] of the ceramics is
not suitable for practical piezoelectric applications. Therefore, special
attention should be paid to obtain KNNLS-based ceramics with
excellent electrical properties.