Hierarchically Interconnected Piezoceramic Textile with a Balanced Performance in Piezoelectricity, Flexibility, Toughness, and Air Permeability

Abstract Softening of piezoelectric materials facilitates the development of flexible wearables and energy harvesting devices. However, as one of the most competitive candidates, piezoelectric ceramic‐polymer composites inevitably exhibit reduced power‐generation capability and weak mechanical strength due to the mismatch of strength and permittivity between the two phases inside. Herein a flexible, air‐permeable, and high‐performance piezoceramic textile composite with a mechanically reinforced hierarchical porous structure is introduced. Based on a template‐assisted sol‐gel method, a three‐order hierarchical ceramic textile is constructed by intertwining submillimeter‐scale multi‐ply ceramic fibers that are further formed by twisting micrometer‐scale one‐ply ceramic fibrils. Theoretical analysis indicates that large mechanical stress can be easily induced in the multi‐order hierarchical structure, which greatly benefits the electrical output. Fabricated samples generate an open‐circuit voltage of 128 V, a short‐circuit current of 120 µA, and an instantaneous power density of 0.75 mW cm −2 , much higher than the previously reported works. The developed multi‐order and 3D‐interconnected piezoceramic textile shows satisfactory piezoelectricity (d 33 of 190 pm V −1 ), air permeability (45.1 mm s −1 ), flexibility (Young's modulus of 0.35 GPa), and toughness (0.125 MJ m −3 ), collectively. The design strategy of obtaining balanced properties promotes the practicality of smart/functional materials in wearables and flexible electronics.