Converting Wi-Fi signals to electricity with new 2-D materials
Device made from flexible, inexpensive materials could power large-area electronics, wearables, medical devices, and more.
Written by Rob Matheson
MIT News

Imagine a world where smartphones, laptops, wearables, and other electronics are powered without batteries. Researchers from MIT and elsewhere have taken a step in that direction, with the first fully flexible device that can convert energy from WiFi signals into electricity that could power our electronics.

Devices that convert AC electromagnetic waves into DC electricity are known as "rectennas." In a newly-published study that appears in Nature, the researchers demonstrate a new kind of rectenna that uses a flexible radio-frequency (RF) antenna that captures electromagnetic waves — including those carrying WiFi — as AC waveforms.

The antenna is then connected to a novel device made out of a two-dimensional semiconductor just a few atoms thick. The AC signal travels into the semiconductor, which converts it into a DC voltage that could be used to power electronic circuits or recharge batteries.

In this way, the battery-free device passively captures and transforms ubiquitous WiFi signals into useful DC power. Moreover, the device is flexible and can be fabricated in a roll-to-roll process to cover very large areas.

"What if we could develop electronic systems that we wrap around a bridge or cover an entire highway, or the walls of our office and bring electronic intelligence to everything around us? How do you provide energy for those electronics?" says paper co-author Tomás Palacios, a professor in the Department of Electrical Engineering and Computer Science at MIT.

"We have come up with a new way to power the electronics systems of the future — by harvesting WiFi energy in a way that's easily integrated in large areas — to bring intelligence to every object around us."