Leveraging giant magnetoelasticity in soft matter for acoustic energy harvesting

To address the challenge of recycling energy from low-density acoustic waves found in everyday sounds such as speech and music, we developed a soft acoustic energy harvester based on the giant magnetoelastic effect. This harvester efficiently captures energy from various environmental sound sources. It operates by combining the giant magnetoelastic effect with a spray-coating and magnetic pre-orientation process, enabling it to convert multi-directional acoustic waves into electrical energy across a wide frequency range (0–900 Hz). The magnetoelastic generator achieves a short-circuit current density of 98 μA cm⁻² at a low internal impedance of 300 Ω, representing a significant improvement in current output that achieves a 100-fold increase compared to existing counterparts for acoustic energy harvesting. With inherent waterproofness and dustproofness, it can function effectively in humid or dusty conditions without extra encapsulation. The acoustic energy harvester demonstrates excellent scalability, making it suitable for diverse applications in sustainable energy systems.