Wi-Fi Networks Could Become the Next Source of Energy

One of the most frequent rituals upon arriving at a new home is requesting the Wi-Fi password. These ubiquitous networks, available at homes, hotels, airports, coffee shops, and other public spaces, provide fast and, frequently, free connectivity. However, they could soon be offering a unique feature — the use of terahertz waves, known as T-rays, found in Wi-Fi signals as an innovative source of energy. Devices like smartphones or smartwatches could thus be recharged in any area within the range of this electromagnetic radiation. This type of energy was so far unusable. Still, researchers at MIT believe that Wi-Fi networks could become a new way of transmitting electricity wirelessly.

Graphene once again

The team, led by Hiroki Isobe, a member of MIT’s Materials Research Lab, recently published an article in the journal Science Advances proving the feasibility of this technology. And not merely on paper, as the researchers are already working on a physical device. Their approach is based on the use of graphene and its behavior on a quantum scale. The team has verified that, by combining graphene with other materials like boron nitride, the electron flux can be controlled and skewed towards a single direction. Thus, the material would deal with terahertz waves as a traffic warden, channeling them through a single lane and transforming them into a direct current (DC).

Previous tests had converted low-frequency radio waves into a direct current but were unable to harvest terahertz waves, which can generate a stronger current. Only the use of ultracold temperatures had offered successful results. Unfortunately, this type of set up precluded most practical applications. The only alternative was to use a clean material, such as graphene, to control the direct current at room temperature.

Working on that principle, Isobe has suggested a small graphene square with a layer of boron nitride and an antenna. Graphene is a symmetric material, which means that electrons receive incoming energy waves from all directions and scatter in all directions too. The use of boron nitride, however, alters the symmetry, as boron attracts electrons in one direction and nitrogen in a different one. This tension steers electrons in a single direction, thus generating a direct current. Researchers compare this technology to a solar PV cell that captures electromagnetic waves instead of sunlight.

 The ultimate energy source for the Internet of Things?

In the next few years, a host of new Internet-enabled microdevices will arrive in the market. All types of sensors, embedded in a wide range of objects, will communicate between themselves and with the network without the need for an Internet browser. The Internet of Things (IoT) is poised to become a gamechanger, but all those devices will need their power sources. Technically, T-rays could be a way o addressing these requirements. Devices such as wearables, pacemakers, or other body implants would also benefit from this wireless charging technology.

Source: MIT