Flexible PVDF/ZnFe2O4 nanofibers-based Magneto-Mechano-Electrical Generator for Energy Harvesting and Sensing Applications

Abstract

The increasing demand for reliable energy sources to power electronic devices in remote and non-contact environments has driven advancements in energy harvesting technologies. Among these, magneto-mechano-electric (MME) harvesters stand out for their ability to generate energy through non-contact magnetic interactions. In this study, we have developed self-biasing, multi-mode flexible MME generators based on PVDF/ZnFe2O4 fibers composites, -designed for efficient and energy harvesting and sensing applications. The ZnFe2O4 magnetic nanofiber fillers have been synthesized and optimized using an electrospinning technique followed by heat treatment. Flexible PVDF/ZnFe2O4 fibers composites have fabricated using the electrospinning process. X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy demonstrated an improved ferroelectric β-phase in PVDF, attributed to the integration of ZnFe2O4 nanofibers. The resulting PVDF/ZnFe2O4 composite exhibited multiferroic magnetoelectric (ME) properties, as confirmed by its ferroelectric and magnetic behaviour. The composite is used to fabricate varsatile MME generators, which demonstrated an impressive output voltage of 7.8 V and a power density of 106 μW/m² under a low alternating current (AC) magnetic field of 6 Oe, about four times higher than a neat PVDF-based MME generator. Furthermore, the device achieved a high magnetoelectric voltage coefficient (αMME) of 130 V cm⁻¹ Oe⁻¹ without a magnetic bias direct current (DC) field. The developed MME generator effectively harvested weak parasitic magnetic noise from various electrical appliances and successfully charged multiple capacitors. In addition to energy harvesting, the device functioned as both a magnetic and stress sensor, demonstrating significant potential for applications in wireless sensor networks and remote powering solutions.