A High-Performance Piezoelectric Nanogenerator Based on MXene/ Metal-Organic Framework (Mxof)-Modified PVDF Nanofibers for Wearable Energy Harvesting and Motion Sensing

The development of electrospun nanofiber-based flexible piezoelectric nanogenerators (PENGs) with capability to convert ambient mechanical stimuli into usable electrical energy have garnered significant interest. Here, a novel strategy for fabricating flexible PENGs was introduced by incorporating a hybrid MXene/metal-organic framework (MXOF) composite into an electrospun PVDF nanofibrous membrane at varying concentration from 1 to 5 wt%. The resulting nanofibrous membranes exhibited uniform, bead-free fibers with diameters ranging from 134 to 261 nm. The MXOF nanoparticles acted as a highly effective nucleating agent, enhancing the electroactive beta-phase fraction within the PVDF matrix by similar to 10%. This elevated beta-phase fraction yielded a significant improvement in piezoelectric output without compromising flexibility, as evidenced by the maximum peak-to-peak voltage of 6.81 V under 2.5 N force for PVDF/MXOF-1 specimen. A PENG with 1 wt% MXOF loading was found to be optimal resulted in a similar to 240% enhancement of the piezoelectric response compared to pristine PVDF nanofibers. Further increases in MXOF concentration led to a decline in piezoelectric performance, presumably due to agglomeration and dipole misalignment. Practical utility of developed PENGs was demonstrated by monitoring human motion, generating maximum outputs voltage of 9.31 V from walking, and 25.46 V from a heel strike. The flexible PENG device also showed excellent long-term stability. These findings demonstrate that MXOF-integration is an effective strategy for enhancing PVDF-based PENGs, proving their potential use in flexible energy harvesting applications.