Enhanced self-poled output performance of flexible and mechanically robust in situ synthesized ZnO/PVDF hybrid piezoelectric composite films for human motion monitoring

Abstract

Piezoelectric nanogenerator (PENG) has been a promising mechanical energy harvester for portable electronic and wearable devices in recent years, yet polymer-based piezoelectric composites with high flexibility and expansibility remain challenging. Herein, an enhanced self-poled strategy for the flexible AgMo@ZnO/PVDF hybrid piezoelectric composite film fabricated via the casting process is coming up to obtain the high-performance PENG. Attributed to the noncovalent crosslinking network formed with modified MoS₂ (g-MoS₂), high-aspect-ratio silver nanowires (AgNWs) and in-situ synthesized ZnO, the AgMo_0.1@ZnO_6.5/PVDF composite film is induced to crystallize and its tensile strength is as high as 62.8 MPa with the assistance of post-annealing treatment. Notably, the electroactive polar β-phase in the composite film is further stimulated to nucleate, where the relative fraction (F(β)) is increased to 83.4 %. Moreover, the composite film is endowed with ultra-high piezoelectric output (22.65V), which is about 16.5 times higher than that of neat PVDF film benefitting from the hybrid networks of enhanced induced charge and β-phase transfer. Taking the above advantages, the AgNWs-TCFs/PENG assembled with AgNWs@SiO₂NPs-TCF exhibited rapid response time, high sensitivity, outstanding reliability, and stability, which can accurately monitor the plane and bending human motions. We believe this work provides a simple and feasible design idea for creating high-performance PENGs, driving the development of PVDF-based flexible piezoelectric devices.