Metastructure Strategies for d33 Enhancement Beyond Intrinsic Limits in 3D-Printed BaTiO3 Metamaterials
High-sensitivity piezoelectric ceramics with high piezoelectric constants (d33) are crucial for miniaturized, low-power, and high-efficiency transducers. However, conventional performance enhancement relies on intrinsic parameter modulation, which is limited and blind. This study introduces a performance-driven metamaterials creation model to develop structure-function-integrated piezoelectric materials. We systematically investigated the effects of metastructure design on d33 across two-dimensional straight rod (SR) structures, three-dimensional dot-matrix (Octa) structures, complex triply periodic minimal surface (TPMS) structures, and hybrid Octa&SR structures. The results demonstrate that metastructures combining high polarization charge conversion efficiency with low compression modulus (stiffness) effectively enhance d33. The SR structure exhibited optimal polarization charge conversion, the Fks-Shellular (FksS) structure within TPMS showed low stiffness, and the Octa&SR structure combined both properties. Notably, all three structures displayed exceptional piezoelectric performance. Specifically, the FksS structure achieved a substantial d33 of 194 pC/N, a 24% enhancement over conventional solid BaTiO3, while maintaining isotropic and stress-insensitive properties. This work elucidates the mechanism for designing piezoelectric metastructures, offering a novel pathway for developing high-performance, high-failure-strength piezoelectric materials.