Enhanced Electromechanical Performance in Lead-free (Na,K)NbO₃-Based Piezoceramics via the Synergistic Design of Texture Engineering and Sm-Modification

Next-generation electromechanical conversion devices have a significant demand for high-performance lead-free piezoelectric materials to meet environmentally friendly requirements. However, the low electromechanical properties of lead-free piezoceramics limit their application in high-end transducer applications. In this work, a 0.96K_0.48Na_0.52Nb_0.96Sb_0.04O₃-0.04(Bi_0.5-xSm_x)Na_0.5ZrO₃ (abbreviated as T-NKN-xSm) ceramic was designed through phase regulation and texture engineering, which is expected to solve this difficulty. Through our research, we successfully demonstrated the enhanced electromechanical performance of lead-free textured ceramics with a highly oriented [001]_c orientation. Notably, the T-NKN-xSm textured ceramics doped with 0.05 mol % Sm exhibited the optimal electromechanical performance: piezoelectric coefficient d₃₃ ≈ 710 pC N^-1, longitudinal electromechanical coupling k₃₃ ≈ 0.88, planar electromechanical coupling k_p ≈ 0.80, and Curie temperature T_c ≈ 244 °C. Finally, we conducted a detailed investigation into the phase and domain structures of the T-NKN-Sm ceramics, providing valuable insights for achieving high electromechanical properties in NKN-based ceramics. This research serves as a crucial reference for the development of advanced electromechanical devices by facilitating the utilization of lead-free piezoelectric materials with superior performance and environmental benefits.