Tailored PVDF-CNC-BiFeO3 electrospun nanocomposites for hybrid energy harvesting: comprehensive investigation into microstructural and electromechanical behavior

This work investigated electrospun Polyvinylidene fluoride (PVDF) incorporated with cellulose nanocrystals (CNC) and bismuth ferrite (BiFeO₃, BFO) to develop a bi-filler nanocomposite membrane for mechanical energy harvesting and sensing applications. The combined influence of electrospinning and nanofillers on crystallinity ratio and β phase formation is studied in detail using a comparative approach. From the analysis of dynamic dielectric responses, changes were observed in interfacial polarization with filler addition, contributing to a deeper understanding of the complex interactions in triphasic nanocomposites. Additionally, the morphology, ferroelectric, and mechanical properties of the nanofibers were also characterized. The practical potential of PVDF-CNC-BFO nanocomposites was demonstrated through the fabrication of piezoelectric and piezo-triboelectric hybrid nanogenerators. The piezoelectric nanogenerator (PENG) based on the bi-filler nanocomposite exhibited a maximum power density of 544 μW/cm³, excellent durability, and capacitor-charging capability. It responded efficiently to diverse mechanical stimuli, including various human motions and cantilever vibrations. The piezo-triboelectric hybrid nanogenerator (PTNG) generated an average open-circuit voltage of 72 V and a short-circuit current of 15 μA under finger tapping, sufficient to power small electronic devices. When integrated with a spring-based structure, the PTNG demonstrated potential for applications such as monitoring road conditions and harvesting energy during vehicle motion. This validated its ability to function as a next-generation self-powered sensor and portable energy harvester.