Enhanced temperature stability in high piezoelectric performance of (K, Na)NbO3-based lead-free ceramics trough co-doped antimony and tantalum

Highlights:• High piezoelectric coefficient (d₃₃ = 510 pC/N) is obtained in KNNTS_x-BSNZ ceramics at x = 0.045 with R-T phase boundary.• An optimal temperature stability (S_uni120°C/S_uniRT = 93.1%, S_uni180°C/S_uniRT = 82.5%) is observed at x = 0.03.• The mechanism of enhanced temperature stability of Ta, Sb co-doped KNN-based ceramics is explained.• The physical origin for the enhanced overall electrical properties has been addressed. -- Abstract: Although KNN-based ceramics with high electric performance have been obtained by phase engineering strategy, the temperature stability is required to be the improved in the applications. Herein, a new environment-friendly 0.96K_0·4Na_0·6Nb_0.97-xTa_0.03Sb_xO₃-0.04(Bi_0.45Sm_0.05)Na_0·5ZrO₃ (KNNTS_x-BSNZ, x = 0–0.08) ceramic system was designed, which exhibits excellent piezoelectric properties and good temperature stability. A high piezoelectric property of 510 pC/N is obtained by R-T phase engineering in the ceramics with x = 0.045. The temperature stability of electric properties is improved in the temperature range of T = 20–180 °C by Ta, Sb co-doping in KNNTS_x-BSNZ ceramics with x = 0.02–0.045, benefiting from the combined effects of both the enhanced relaxor behavior and high T_C. Therefore, we believe that it can broaden the application of KNN-based ceramics.