Goodbye batteries! In the future, smartphones will capture energy from wi-fi


Recharging the batteries could one day become an ancient memory. A team of MIT researchers has indeed succeeded in developing a system capable of converting the energy associated with wi-fi signals into electrical energy, theoretically eliminating the need for the very existence of a traditional battery.

The idea, not really unpublished, exploits the physical principle of the rectenna: the word is the contraction of rectifying antenna, which is a grid antenna able to capture electromagnetic waves, for example those of wi-fi, and to transform them in direct current.

This is nothing new. The traditional rectenes were made of silicon or gallium arsenide, which are quite expensive and rigid materials, therefore not very "adaptable" to be introduced into pocket-sized electronic devices or, worse, flexible as they might be in the future. The novelty is right here: the rectenna designed by the team of Tomás Palacios, a professor at the Department of Electrical Engineering and Computer Science at MIT, uses molybdenum sulfide, a super thin semiconductor that can be modeled in sheets as thick as the main component. just 3 atoms.

This material can be bent and deformed at will without losing its efficiency in the conversion of electromagnetic waves into electrical current.

The first prototypes manage to capture and convert the energy associated with the wi-fi signal with an efficiency of about 30%: we talk about power that is certainly not exceptional, but sufficient to power small wearable devices or sensors for medical and diagnostic use that in this way they could do without traditional batteries.

Yes, but then? Interesting, then, but: what practical applications could such technology have in the future? Among the features that could be exploited of this new type of rectenna, there is the possibility of "spreading" it on walls or floors: according to Palacios it could in fact be obtained a version of his invention of much larger dimensions, which can be used for power the connected devices of an entire building or the entire sensor network of an intelligent highway.