Robust magnetic energy harvesting with flexible lead-free poly(vinylidene fluoride)-Ba0.85Ca0.15Ti0.9Zr0.1O3 fibers and Metglas-based magnetoelectric composites

Abstract

The integration of magnetoelectric (ME) principles using magneto-mechano-electrical (MME) generators enables the construction of self-powered wireless sensor networks (WSNs) for mechanical energy harvesting. In this study, we propose a lead-free, flexible MME generator that incorporates poly(vinylidene fluoride) (PVDF)/Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃ (BCZT) fiber composites and Metglas. This generator produces a robust output voltage even in the presence of stray magnetic fields, without requiring a magnetic bias field. We prepared flexible PVDF/BCZT fiber composites by electrospinning the components at various proportions, and a magnetostrictive Metglas layer was incorporated during the ME composite fabrication process. Under resonance conditions (50 Hz), the optimized ME composition yielded a maximum ME voltage of 472 V cm⁻¹ Oe⁻¹ without a magnetic DC bias field. This significant improvement is attributed to the interfacial interactions between the surface of inorganic BCZT nanoparticles and dipoles within the PVDF polymer matrix, as well as the high permeability of Metglas. Additionally, the flexible MME generator proposed in this study produced an open-circuit voltage of 14.8 V and an approximate power density of 4.7 µW cm⁻³ under an AC magnetic field of 10 Oe with a frequency of 50 Hz. We demonstrate that our MME device can be used to monitor the health of a muffle furnace by tapping into the magnetic field noise coming from its electronic cables. The as-developed lead-free flexible MME generator shows potential for advanced applications in self-powered WSN and energy harvesting technologies.