Ultrahigh piezoelectric performance benefiting from quasi-isotropic local polarization distribution in complex lead-based perovskite

Materials with high piezoelectricity have always been the pursuit of both industrial production and scientific research. Designing new high-piezoelectricity materials and establishing the structure-performance relationship are crucial for those two aspects. Here, a complex perovskite system with excellent comprehensive properties (d₃₃ = 920 pC/N, d^*₃₃ = 902 pm/V, T_m = 120 °C, k_p = 0.62) is developed, and taken as a case study to explain the origins of high piezoelectricity utilizing atomic-resolution scanning transmission electron microscopy and in situ high-energy synchrotron X-ray diffraction. Correlated local multiple polar symmetries coexistence with a quasi-isotropic local polarization distribution result in a long-range average pseudo-cubic phase. The reduced local polarization anisotropy and the flexible polarization configuration promote a continuous polarization rotation between different polarities, leading to a large field-induced lattice strain and ultimately generating high piezoelectric performance. This work provides a perspective that decreased polarization anisotropy at the local scale is beneficial to the enhancement of high piezoelectricity, which will facilitate the design and development of new piezoelectric materials.