Metastructure strategies for d₃₃ enhancement beyond intrinsic limits in 3D-printed BaTiO₃ metamaterials

High-sensitivity piezoelectric ceramics with high piezoelectric constants (d₃₃) values are of significant research value, because they facilitate the miniaturization, low-power, and high-efficiency characteristics of transducer devices. However, the development of traditional piezoelectric ceramics relies on the modulation of intrinsic parameters with both limited and blind performance enhancements. In contrast, a performance-driven metamaterials creation model provides new ideas for the development of structure-function-integrated high-performance piezoelectric materials. In this study, the effects of the d₃₃ were systematically investigated in species ranging from two-dimensional straight rod (SR) structures to 3D dot-matrix (Octa) structures, and from simple dot-matrix structures to complex triply periodic minimal surface (TPMS) structures and hybrid structures (Octa&SR). It was found that the metastructure design, characterized by both a high polarization charge conversion rate and a low compression modulus (stiffness), constituted an effective means for enhancing d₃₃. The SR structure demonstrated the optimal polarization charge conversion rate, the Fks-Shellular (FksS) structure in the TPMS structures exhibited low stiffness values, and the Octa&SR structure exhibited both properties. Notably, all three structures exhibited exceptional piezoelectric properties. Moreover, the FksS structure demonstrated a substantial d₃₃ (194 pC/N) enhancement of 24% compared with that of the conventional solid structure, while exhibiting isotropic and stress-insensitive properties with optimal structure-function integration. Overall, this study elucidates a mechanism for the design of structures exhibiting desirable piezoelectric properties, thereby providing a novel concept for the future development of high-performance and high-failure-strength piezoelectric materials. (Figure presented.)