High‐Efficiency Toroidal Magnetoelectric Wireless Power Transfer in Conductive Media

Wireless power transfer (WPT) in conductive environments such as seawater and biological tissue is fundamentally constrained by eddy‐current losses, which strongly attenuate magnetic fields and degrade efficiency. Magnetoelectric (ME) receivers have been explored as a potential solution for implantable and compact devices, but their reported efficiencies at centimeter‐scale distances remain very low, limiting practical applications. Here, we present a toroidal ME WPT (TME‐WPT) system that integrates flux‐concentrating Metglas laminates with a resonance‐assisted receiving coil to overcome these limitations. The toroidal transmitting coil was adopted as a conceptual design for biomedical applications, where a large loop could potentially encompass the human body, enabling efficient coupling to implanted devices. At the same time, the Metglas laminates enhance magnetic flux concentration, and resonance improves the coupling performance of the receiver. Experiments demonstrate transfer efficiencies exceeding 60% across a distance of 20 cm in seawater, while simultaneously delivering output powers of up to 2 W. These results represent an orders‐of‐magnitude improvement over previous ME‐based systems and establish a compact, low‐frequency architecture capable of efficient long‐range energy delivery. The proposed TME‐WPT platform provides a promising solution for powering biomedical implants and underwater electronic systems in environments more conductive than air.