Elastic Droplet-Based Magnetoelectric Generator for High-performance Energy Collection

Conventional magnetoelectric generators are regarded as effective devices for harvesting concentrated hydraulic power but are ineffective for dispersed hydropower (e.g., raindrops) due to their bulkiness and immobility. Here, we propose a superhydrophobic magnetoelectric generator (MSMEG) based on an elastic magnetic film that can efficiently convert the energy of lightweight water droplets into electricity. The MSMEG consists of five parts: a superhydrophobic magnetic material-based film (SMMF), a coil, a NdFeB magnet, an acrylic housing, and an expandable polystyrene (EPS) base. The SMMF with coil can deform/recover when droplets impact/leave the MSMEG, resulting in a peak current, peak charge density, and peak power density of ∼13.02 mA, ∼1826.5 mC/m2, and ∼1413.0 mW/m2, respectively, with a load resistance of 47 Ω. Related working mechanism is analyzed through Maxwell numerical simulation, which is used for further guidance on increasing the electrical output of the MSMEG. Furthermore, the MSMEG can quickly charge a commercial capacitor with 2.7 V/1 F to 1.18 V within 200 s and power diverse electronic devices (e.g., light emitting diodes (LEDs), fans) with constant excitation by water droplets. We believe that such an MSMEG is expected to provide a promising strategy for efficiently harvesting dispersed raindrop energy.