Battery-less phones could be reality soon

Scientists have made a huge breakthrough that allows them to convert radio signals into power. The discovery could allow for phones and other devices that don’t use batteries — as well as entirely new ways of using smart technologies.

Scientists in the US developed the device, known as a “rectenna”, from a semiconductor just a few atoms thick.

Wi-fi signals captured by an integrated antenna are transformed into a DC current suitable for electronic circuits. The device could be used to provide battery-less power for smartphones, laptops, medical devices and wearable technology, according to the US-led team.

Because of its flexibility, it could also be fabricated to cover large areas. This has major implications for the future of “electronic intelligence”, say the scientists.

Professor Tomas Palacios, director of the Massachusetts Institute of Technology said: “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?

“We have come up with a new way to power electronics of the future — by harvesting wi-fi energy in a way that’s easily integrated in large areas — to bring intelligence to every object around us.”

In experiments, the rectenna generated about 40 microwatts of power when exposed to typical wi-fi signals of 150 microwatts. That is more than enough to light up a simple mobile display or activate silicon chips. The research is published in ‘Nature’.

Co-author Professor Jesus Grajal said a key application could be in medical implants and “pills” that stream health data after being swallowed. “You don’t want to use batteries to power these systems. If they leak lithium, the patient could die.”