Small-displacement mechanical energy harvesting through magnetic phase transition materials

<p>Our daily environment contains abundant vibrational and impact energies characterized by high instantaneous stress yet minimal displacement. These inherent characteristics present fundamental conversion challenges for traditional generators, which require substantial relative motion between magnetic and conductive components to induce effective current generation. To address this limitation, we propose an innovative method of low-displacement mechanical energy harvesting that utilizes piezomagnetic effects during pressure-induced magnetic phase transitions. By doping germanium into the silicon site of MnCoSi, the magnetic phase transition material MnCoSi<sub>0.88</sub>Ge<sub>0.12</sub> exhibits excellent piezomagnetic properties over a broad temperature range. Our meticulously designed piezomagnetic power prototype device features a magnetic circuit that enhances magnetic flux within the induction coil. Using MnCoSi<sub>0.88</sub>Ge<sub>0.12</sub> as the working substance, the prototype is rigorously tested under various temperatures and pressures, exhibiting intriguing performance from 250 to 325 K, covering room temperature. Notably, the prototype device, which is devoid of moving parts, has achieved a peak power density of 34.4 μW/cm³. The device's ability to harvest energy from small-displacement vibrations and instantaneous impacts, such as those from heavy machinery or geological activities, highlights its potential for applications in mobile energy supply. This work also provides a path toward self-powered vibration and impact sensor networks in harsh and unattended environments.</p>