MXene‐Doped P(VDF‐TrFE) Piezoelectric Spring‐Structured Devices for Vibration Sensing and Sleep Monitoring

Driven by the rapid development of artificial intelligence and the internet of things, flexible piezoelectric polymers and smart sensors have emerged as core research focuses on flexible electronics. Polyvinylidene fluoride (PVDF) and its copolymer P(VDF‐TrFE) stand out for outstanding flexibility, easy fabrication, stable chemical properties, and biocompatibility, holding great promise for flexible sensing and mechanical energy harvesting. However, their inferior piezoelectric coefficients restrict large‐scale practical use relative to inorganic piezoelectric counterparts. Nanofiller doping and three‐dimensional structure design are proven to be efficient ways for improvement of their piezoelectric performance. Herein, MXene‐modified P(VDF‐TrFE) nanofiber piezoelectric devices with 3D spring architecture are prepared through electrospinning and shaping methods for synergistic performance enhancement. The optimized composite film obtains a piezoelectric coefficient of −20.1 pC/N, about 62.1% enhancement compared with pristine samples. The 3D spring structure further improves mechanical adaptability and electric output capacity. The assembled vibration energy harvester reaches a power density of 35.4 mW/m 3 under a 20 MΩ load. Moreover, the fabricated device enables vibration frequency detection and real‐time human sleep monitoring, showing vast application potential in industrial sensing and smart health monitoring.