Confined orientation PVDF/MXene nanofibers for wearable piezoelectric nanogenerators

Abstract

The quest for high-performance wearable piezoelectric nanogenerators (PENGs) has intensified the focus on polyvinylidene fluoride (PVDF). The optimization of piezoelectric response in these nanofibers has traditionally been impeded by the difficulty in uniformly distributing the piezoelectrically active β-phase, leading to variable material characteristics and inconsistent device performance. Here, we propose a novel confined orientation structure of PVDF/MXene nanofibers, which significantly improves electromechanical performance without sacrificing flexibility. By incorporating MXene into the PVDF matrix, we successfully induce the formation of the β-phase, achieving a piezoelectric coefficient of 61.7 pC N⁻¹. This integration facilitates a synergistic enhancement of material and structure, leading to a high degree of orientation and confinement of MXene nanosheets within the fibers, which optimizes force transfer and enhances energy harvesting capabilities. Consequently, the nanofiber-based PENG demonstrates an exceptional response time of 14 ms and a pressure sensitivity of up to 19.29 mV kPa⁻¹. This work paves the way for advanced self-powered sensing technologies and mechano-electrodeposition applications, underscoring the pivotal role of PVDF-based nanofibers in the evolution of wearable PENGs.