Piezoelectric nanogenerators (PENGs) are promising for efficient nanoenergy harvesting, yet their output is often limited by disruption of the active phase by nonpolar phases. Here, we introduce a postelectrospinning hot-stretching treatment after conjugated electrospinning to precisely regulate the microcrystalline morphology of a poly(vinylidene fluoride) (PVDF) nanofiber yarn (NY). This strategy increased the lamellar long period and lateral size of the resultant NY, yielding a highly regular crystalline structure with ∼60% crystallinity and ∼93% β-phase content. Consequently, the optimized PVDF NY achieved a fracture stress of 65 MPa, a 444% improvement over the pristine sample. The piezoelectric output also rose by 366.7%, from 0.3 to 1.4 V. These enhancements highlight hot stretching as an effective approach to simultaneously improving the mechanical and electrical properties of a PVDF NY. This work provides a new pathway for developing high-performance PENGs with significant potential in sustainable energy-harvesting applications.
Zhang et al. (Thu,) studied this question.