Abstract
Self-powered wearable electronics for real-time physiological monitoring require mechanical energy harvesters that simultaneously offer high sensitivity, flexibility, and power density, yet most existing piezoelectric nanogenerators struggle to efficiently convert low-frequency biomechanical energy under these constraints. In particular, polyvinylidene fluoride (PVDF)-based composite fibers often suffer from limited interfacial charge transport and insufficient piezoelectric response, which restricts their use in practical, textile-integrated devices. Here, we develop a high-performance piezoelectric composite fiber, PZT-OV/Ti3C2Tx/PVDF, by electrostatic spinning self-assembly of oxygen vacancy–engineered lead zirconate titanate (PZT-OV), MXene (Ti3C2Tx), and PVDF. The resulting prickly-fibril interfacial structure between PZT-OV and Ti3C2Tx enables ultrafast carrier transport and enhanced mechanosensitive, yielding flexible piezoelectric nanogenerators (PENGs) with a 15-fold increase in current density under compression. Optimized devices deliver a peak power density of 4.78 μW cm−2, a sensitivity of 1.46 V kPa−1, and an energy conversion efficiency of 14.8%. Integrated into wearable textiles, these PENGs harvest subtle biomechanical energy and wirelessly transmit data via Bluetooth, enabling self-powered monitoring of body temperature and heart rate. These results demonstrate that combining oxygen vacancy engineering with MXene-assisted interfacial design in electrospun fibers is an effective strategy for advancing high-performance, self-powered wearable biosensing systems.