Wireless power transfer based on novel physical concepts

Wireless power transfer—the transmission of electromagnetic energy without physical connectors such as wires or waveguides—typically exploits electromagnetic field control methods that were first proposed decades ago and requires some essential parameters (such as efficiency) to be sacrificed in favour of others (such as stability). In recent years, novel approaches to electromagnetic field manipulation have been developed that can be used to create advanced forms of wireless power transfer. Here we review the development of novel physical effects and materials for wireless power transfer. We explore techniques based on coherent perfect absorption, parity–time symmetry and exceptional points, and on-site power generation. We also explore the use of metamaterials and metasurfaces in wireless power transfer, and the use of acoustic power transfer. Finally, we highlight potential routes for the further development of wireless power transfer technology. This Review examines the development of novel physical effects and materials for wireless power transfer, considering techniques based on coherent perfect absorption, parity–time symmetry and exceptional points, and on-site power generation, as well as the use of metamaterials and metasurfaces, and acoustic power transfer.