Wide‐Stable Dynamics Enabling Ultra‐High Power Density in Compact Magneto‐Mechano‐Electric Energy Harvesters for Self‐Powered Smart Grid Monitoring

ABSTRACT

Cantilever‐structured magneto‐mechano‐electric energy harvesters (MME‐EHs) are considered as one of promising candidates for powering Internet of Things (IoT) devices by capturing ambient magnetic fields. However, conventional MME‐EHs with volumes comparable to button cell batteries (≤1 cm ³ ) face a critical challenge in overcoming the output power density bottleneck to meet advancing IoT demands under weak excitations. In this work, we overcome this limitation by proposing a wide‐stable energy harvesting strategy. Unlike conventional bistable systems that struggle to sustain high‐energy interwell oscillations under weak excitations, or monostable systems restricted by steep potential wells, our design leverages nonlinear dynamics to engineer a broadened and flattened potential well that facilitates large‐amplitude intrawell motion even under weak fields. This strategy significantly enhances magneto‐mechanical coupling efficiency, enabling a compact MME‐EH (effective volume 0.968 cm ³ ) to generate 0.89 mW output power under a weak magnetic field of 1 Oe at 50 Hz, representing an 89% enhancement over the original MME‐EH. The output power density reaches 0.92 mW cm ⁻³ Oe ⁻² , revealing a 26% improvement compared to state‐of‐the‐art performance. Its potential for practical application is validated via a self‐powered wireless sensor network (WSN) for grid monitoring and fire alarms, paving the way for maintenance‐free, wide‐area distributed WSNs.