You would love to own a smartphone that could be powered without batteries. Won’t you? Taking an effective step in that direction, researchers from MIT and the Technical University of Madrid have developed a fully flexible device that can garner energy from Wi-Fi signals to directly power devices wire-free/battery-free.

For the uninitiated, a device that converts AC electromagnetic waves into DC electricity is called “rectenna”. The MIT version of rectenna uses a flexible radio-frequency (RF) antenna that captures electromagnetic waves — including those carrying Wi-Fi — 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 is able to passively capture and transform Wi-Fi signals into useful DC power. The best part about the device is that it is flexible and can be fabricated in a roll-to-roll process to cover very large areas.