New Potassium–Sodium Niobate Ceramics with a Giant d33

For potassium–sodium niobate, poor piezoelectric properties always perplex most researchers, and then it becomes important to attain a giant piezoelectricity. Here we reported a giant piezoelectric constant in (1 – x )(K 0.48 Na 0.52 )(Nb 0.95 Sb 0.05 )O 3 - x Bi 0.5 Ag 0.5 ZrO 3 lead-free ceramics. The rhombohedral-tetragonal phase boundary was shown in the ceramics with 0.04 < x ≤ 0.05, and then the ceramic with x = 0.0425 possesses a giant d 33 of ∼490 pC/N. We also discussed the physical mechanisms of enhanced piezoelectricity. As a result, such a research can benefit the sustainable development of (K,Na)NbO 3 materials.