Grain Boundary Segregation-Induced High-Performance Piezoelectric Ceramics

Piezoelectric ceramics, which can convert mechanical energy into electrical energy and vice versa, are the cornerstone of modern technologies including sensors, actuators, and transducers. Despite their widespread applications, the strategies for fundamentally optimizing their piezoelectric performance have remained remarkably limited, primarily revolving around constructing morphotropic phase boundaries, enhancing disorder, and texturing. Here, we report that grain boundary segregation can act as an alternative strategy for achieving high-performance piezoelectric ceramics. We demonstrated this concept in the classical tungsten-doped bismuth-layered structure ceramics, where tungsten does not behave as a chemical substitution in the crystal lattice as traditionally assumed, but adsorbs orderly at the grain boundaries. Consequently, the segregation contributes to a resistivity improvement by 2-3 orders of magnitude, leading to a rise in the piezoelectric coefficient. The resulting sensors also exhibit exceptional temperature stability. Our study not only provides an alternative strategy for designing high-performance piezoceramics but also enriches grain boundary engineering in polycrystalline materials.