Electrospun Poly(vinylidene fluoride)-Based Nanogenerator Modified by Rutile/Anatase-Heterostructured TiO₂ Nanorods for Piezoelectricity

Nowadays, piezoelectric nanogenerators (PENGs) based on poly(vinylidene fluoride) (PVDF) have exhibited extensive potential applications in wearable electronics. Improving the piezoelectric performance of PVDF-based PENGs through low-cost and nontoxic fillers is an attractive technology for industrial applications. Herein, we propose a superior piezoelectric performance of PVDF-based PENG with cheap and nontoxic TiO2 nanorods as the regulated fillers. The built-in electric field of the constructed heterostructures in mixed-phase (anatase-rutile) TiO2 nanorods enriches the formation of electroactive beta-phase (87.6%) in PVDF. Moreover, the piezoelectric output of the TiO2@PVDF-based PENG (TP-PENG) reaches 42.5 V, which is 15.7 times higher than the pure PVDF-based PENG with the same electrospinning process. The TP-PENG exhibits superior durability within 9000 cycles, being capable of charging the capacitors, powering the diode light-emitting diode (LED) lights, and monitoring real-time human movements. This promotes the great potential of the PENG for a variety of applications, including biomechanical energy harvesting, motion sensing, and powering microelectronic devices. Most importantly, this study demonstrates that the strategy of controlling phase transition and switching between crystal structures is of great relevance to extending the kinds of possible regulating fillers to enhance the performance of PVDF-based PENGs. It provides a promising low-cost and nontoxic approach for the development of high-performance PENGs.