Magnetic Field and Ultrasound Induced Simultaneous Wireless Energy Harvesting Using Magnetoelectric Transducer for Biomedical Implants

Wireless energy harvesting is a promising technology that can be seamlessly integrated into various electronics systems. However, one of the primary obstacles in harnessing wireless power transfer for implantable medical devices is the inherent limitations associated with transducer alignment sensitivity and low power capacity within safety limits. Consequently, there is a pressing need to develop wireless technologies with robust power capabilities. To address this challenge, researchers have explored the use of magnetoelectric devices based on hard piezoelectric materials. These devices can harvest magnetic fields while adhering to safety regulations when operating in air, liquid, or tissue media. A prototype device, with a volume of 0.075 cm³is demonstrated to harvest magnetic and ultrasound energies simultaneously from a single device traveling through liquid/tissue media generating an ultra-high rms power of ∼52.1 mW across input of ∼500 μT rms magnetic field and ∼675 mW cm⁻² ultrasound intensity, which are below the safety limits prescribed by the IEEE and FDA. This represents an ∼225% improvement compared to individual magnetoelectric systems utilizing a single source under safety limits. The device can recharge a 3 V lithium-ion battery with 1 mA-h capacity at a rate of ∼1.67 mC ^s−1 in porcine tissue. Furthermore, the device has excellent cell viability (85–90%) with limited cytotoxicity and is promising for biomedical implants. These findings demonstrate that the dual energy harvester based on magnetic field and ultrasound intensity has the potential to power wide range of biomedical devices.