Ultra-thin device helps pedestrians charge their phone batteries

At just 1/5000th the thickness of a hair, the new device can extract energy even when we move very gently and slowly.

Scientists at Vanderbilt University, USA have just created a tiny energy-harvesting material that can extract energy from human movement.

The product can be placed in layers of clothing to charge as we move around every day. The electricity collected can be used to charge smartphones, tablets or other personal electronic devices.

New device harnesses excess energy from human movement.

“In the future, I hope we will all be able to charge our personal devices by harvesting energy directly while moving,” said Cary Pint, a researcher on the project.

In the past, there have been many studies conducted with the aim of harvesting available energy sources around such as extracting energy from vibrations and deformations; pulling energy from temperature changes, or harvesting energy from light, radio waves and other forms of radiation...

However, one valuable energy source that has been overlooked is the excess energy from human movement. Although some scientists have created some materials, they can only operate well at frequencies of more than 100 times per second, which most normal human movements cannot reach.

At just 1/5000th the thickness of a hair, the new device can extract energy even when we move very gently and slowly.

“Compared to other materials, this material has two fundamental advantages: one is thickness, the other is sensitivity,” Pint says. “The material is so thin and small that it can be attached to layers of thread without affecting the feel of the fabric. Notably, it can harvest energy from movements slower than 10 Hertz (10 times per second), which corresponds to human movement.”

In the study, the scientists used graphene and two layers of black phosphorus - a material that has always attracted nanotechnologists because of its electro-optical and electrochemical properties.

The energy harvester is created by placing graphene (an electrolyte) between two identical black phosphorus electrodes. The electrodes are created through a chemical process where the black phosphorus layer interacts with this electrolyte.

Together, the 2D materials have the ability to bend and generate energy.

Researchers are testing on a prototype.

The team's prototype design can generate energy from movements below 10 Hertz (10 movements/second) and even 0.01 hertz (1 movement/100 seconds).

When asked about the safety of the material, Pint confidently said that users will never see this device short-circuit, leading to fire or explosion like many other electrical products.

“Batteries typically burn out when the positive and negative electrodes of the device are consumed; in this new material, because there are two identical electrodes, the consumption only affects the ability to produce electricity,” Pint added.

In the future, the team will continue to improve to increase the ability to extract electricity from the device because at present, the new device harvests relatively low voltages in the millivolt (mV) range.

According to Khoahoc.tv