Multi-scale thermal stability of niobate-based lead-free piezoceramics with large piezoelectricity

Abstract

Growing environmental concerns are pushing the development of lead-free piezoceramics with both outstanding piezoelectric properties and reasonable thermal stability. Herein, we realized a large piezoelectric coefficient d₃₃ of 430 pC N⁻¹ in 0.96(K_0.4Na_0.6)(Nb_0.96Sb_0.04)O₃–0.04Bi_0.5K_0.5Zr_0.85Sn_0.15O₃ (KNNS–BKZS) polycrystals by constructing a rhombohedral–tetragonal (R–T) phase boundary. Investigations of the in situ thermal stability of the piezoelectric properties on multiple scales reveal that the micro-scale piezoelectric response is much more stable compared to the macro-scale response, indicating the significant role of extrinsic contributions from domain wall movements. These findings demonstrate the relationship between multi-scale properties and domain structures, revealing that the high piezoelectricity is attributed to nano-domains at the R–T phase boundary.