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.