Porous piezoceramics exhibit enhanced voltage output response, demonstrating significant potential for applications in piezoelectric sensors. In this study, four types of PZT-based porous ceramics with triply periodic minimal surface structures were fabricated using digital light processing (DLP). By controlling the powder morphology and debinding process, composite porous ceramics with coexisting periodic macropores and random micropores, as well as simple porous ceramics with only periodic macropores, were prepared. The results reveal that random pores more effectively reduce the permittivity, however, the increased coercive field and reduced breakdown strength lead to a significant deterioration in the piezoelectric coefficient (d₃₃). In contrast, simple porous ceramics, featuring dense ceramic phases, exhibit higher breakdown strength and lower coercive field, enabling more effective poling. Notably, the Gyroid structure achieves a high d₃₃ of 585 pC/N, comparable to bulk ceramics, while the relative permittivity is significantly reduced to 706. Consequently, an outstanding piezoelectric voltage constant (g₃₃) of 93.3 mV⋅m·N⁻¹ and a high piezoelectric energy harvesting figure of merit of 54.6 × 10⁻¹² m²/N are achieved, far surpassing conventional random porous ceramics. These findings highlight that DLP technology and the development of artificial periodic porous ceramics provide a promising pathway for the design of high-performance piezoelectric devices.

The flexoelectric effect is a mechanical-electric coupling effect between strain gradient and electric polarization (i.e., positive flexoelectric effect) or electric field strength gradient and mechanical strain (i.e., converse flexoelectric effect). Unlike the piezoelectric effect, the flexoelectric effect, which is not limited by material symmetry and the Curie temperature, increases with decreasing the material size, thus attracting much attention and having a promising application. This review introduced the history of flexoelectric effect, measurement of flexoelectric coefficient, and mechanism to enhance flexoelectric effect. Recent studies on its application in the realm of sensors, actuators, mechanical memories, flexoelectric piezoelectric composites, energy harvesters, and electronic devices were highlighted. In addition, the further development of flexoelectric effect was also prospected.