Recent progress on flexible poly(vinylidene fluoride)-based piezoelectric nanogenerators for energy harvesting and self-powered electronic applications

For solving the problem of powering wearable electronic devices, flexible poly(vinylidene fluoride) (PVDF)based piezoelectric nanogenerators (PENGs) developed by integrating PVDF-based PENGs with textiles are becoming a lightweight, green, and sustainable energy solution but show low piezoelectricity. This study reviews and critically discusses the recent advances in flexible PVDF-based PENGs for energy harvesting and self-powered electronic applications. The key to improving the piezoelectric output performance of PVDF-based materials is to increase the beta content. Electrospinning can improve the beta content; thus, electrospun composite fiber-based PENGs exhibit high output performance. 3D printing can realize self-poling PVDF-based PENGs, which provides a new approach to free-poling piezoelectric devices. In addition, yarn-based PENGs have the advantages of processability and structural versatility compared to fabric-based PENGs, which may become an important research direction in this field. PVDF-based PENGs are widely used in self-powered sensors, and wearability and sensitivity should be further investigated in the future based on the improvement of output performance.