Ultrahigh β-Phase Content Polyvinylidene Fluoride/Boron Nitride True-Nanoscale Fibers Based Composites for Stable and Highly Sensitive Self-Powered Flexible Sensors

Abstract

Wearable sensors are an essential component in the advancement of the smart era, yet significant challenges remain in terms of structural performance and self-powering capabilities. Here, we first present an electrospinning strategy to uniformly incorporate BN nanoparticles within continuous true-nanoscale PVDF fibers (22±15 nm), achieving an ultrahigh β-phase content (99.1%) and fabricating a single-layer (macro) ~ multi-layer (micro) composite materials with high-sensitivity and self-powered properties. The key factor is not only harnessing the high piezoelectric properties of PVDF/BN but also ingeniously integrating the triboelectric phenomenon within the fibrous network, resulting in a synergistic piezoelectric-triboelectric coupling effect. This coupling effect significantly enhances the electrical output performance, enabling the composite to function as a highly sensitive pressure sensor (≤5 N-9.70 V/N), ≥10 N-2.32 V/N), suitable for monitoring laryngeal vibration and various human activities and serving as a micro-switch for alarms. When employed as a nanogenerator, the power density of 0.243 W/m², capable of lighting 96 commercial LED bulbs with tapping. Moreover, it was found that using only a small number of nanoparticles (with material savings exceeding 92%) significantly enhances the performance of true-nanoscale fibers. This work offers a novel approach for designing advanced and sustainable high-performance materials.