A novel concept of hierarchical porous structural design on enhancing output performance of piezoelectric nanogenerator

Piezoelectric materials have been deemed as renewable power resources for the applications of harvesting mechanical energy and powering electronics for decades, due to their conspicuous mechanical and piezoelectric properties. Since the piezoelectric voltage is determined by the parameters such as applied force, piezoelectric and dielectric constant, it is crucial to study on tailoring these impact factors to realize a significant performance. In this work, the hierarchical porous PVDF/BaTiO3 foams (PBfs) are designed via salt-template method to modulate those impact factors. The synergistic effect of BaTiO3 and space-charged electret (SCE) formed by pores after poling on enhancing piezoelectric and ferroelectric properties has been firstly explored. The maximum open-circuit voltage and short-circuit current of PBf-30 realize 25.66 V and 677.45 nA after poling under a small applied force of 2 N, respectively. Attributed to the decent mechanical properties and prominent piezoelectric performance, the PBf is applied as the wearable sensor for human body motions and real-time monitor for vehicle movements. This work manifests a novel concept of enhancing output performance by hierarchical porous structural design and paves a way for the potential of piezoelectric nanogenerators in large-scale applications.