Magneto-mechano-electric energy harvesting for sustainable IoT and next-generation electronics: Materials strategies, device engineering, and challenges

초록

Magneto-mechano-electric (MME) generators have recently appeared as promising power sources for autonomous Internet of Things systems, onboard power supply, and potentially long-term maintenance-free operations. These devices exploit abundant low-frequency stray magnetic fields of 50/60 Hz generated by power transmission lines, electrical infrastructures, and industrial equipment. Recently, progress in MME technology has been made from the traditional electromagnetic induction configuration to mechanically resonant cantileverbased configurations, which have higher efficiency under low-frequency excitation. State-of-the-art generators have combined soft magnetostrictive materials such as Metglas, Galfenol, Ni/Fe-Ga alloys, with highperformance piezoelectric materials like lead zirconate titanate (PZT) and lead magnesium niobate-lead zirconate titanate (PMN-PZT) single crystals, and single-crystal fibre composites. Hybrid MME strategies have been developed that incorporate additional transduction mechanisms, such as triboelectric, electromagnetic, or multimode magnetoelectric coupling, to improve output stability and broaden the operational bandwidth. Further, structural innovations such as tuning-fork geometries and bioinspired multi-beam architecture have improved strain utilisation and reduced mechanical losses. Consequently, several reported devices achieve peak power outputs close to 72 mW and average power levels greater than 25 mW under weak magnetic fields, while selfbiased designs based on [011]-oriented PMN-PZT fibre composites demonstrate normalised power densities up to 46.3 mW/cm3.Oe2 in the absence of external magnetic bias. Such performance enables direct powering of wireless sensor nodes, Bluetooth modules, and environmental sensors, besides charging LiFePO4 batteries to support continuous operation of high-power IoT sensor networks. Collectively, these advances underscore the growing potential of single-mode and hybrid MME generators as scalable energy harvesting solutions for smart infrastructure and industrial applications.

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