Magnetic Flux Engineering with Metglas Concentrators for High-Performance Magneto-Mechano-Electric Energy Harvesting

Abstract

Magneto-mechano-electric (MME) generators have attracted increasing attention as efficient energy harvesters for converting ambient magnetic fields into electrical power for self-powered IoT sensor networks. However, their output performance remains limited by insufficient magnetic excitation. Here, we report a high-output MME generator enabled by a magnetic flux concentrator (MFC) fabricated from stacked high-permeability Metglas. By engineering the magnetic environment and the spatial coupling between the MFC and the MME generator, and by optimizing the magnet configuration and the number of MFC layers through finite element analysis and experiments, the magnetic force-driven bending excitation of the cantilever is significantly enhanced. As a result, the proposed MME generator delivers maximum output power (normalized power) of 8.65 mW (0.43 mWOe -2 cm -3 ) under alternating magnetic field of 10 Oe at 60 Hz, substantially outperforming previously reported cantilever-based MME systems. The harvested energy is sufficient to illuminate 120 white LEDs and to charge a 0.1 F supercapacitor to 4 V within 13 minutes. These results demonstrate that high-permeability Metglas-based flux concentration, combined with rational magnet positioning, provides an effective pathway toward practical, high-performance magnetic energy harvesting under realistic ambient conditions.