Engineers from the University of Massachusetts Amherst, in the USA, report having managed to extract electricity from the humidity of the air, that is, from the water vapor found in the environment. “We are opening a door to harvest clean energy from nothing,” says Xiaomeng Liu, one of the authors of the study, published in the journal Advanced Materials.
As there is always humidity in our environment, whether at low or high levels, the team of experts highlights that this process of capturing energy could work 24 hours a day, seven days a week, since it would not have to wait for the optimal conditions of nature that do require other renewable energies, such as solar or wind.
An artificial cloud and an energy harvesting device
“The air contains an enormous amount of electricity,” Jun Yao, lead author of the study, said in a statement.
“Think of a cloud, which is nothing more than a mass of water droplets. Each of those droplets contains a charge, and when conditions are right, the cloud can produce lightning. However, we don’t know how to capture electricity from lightning in a reliable way,” he adds.
As a solution to that problem, Yao and his team developed a method to extract energy from water vapor that consists of a small-scale artificial cloud that produces electricity in a predictable and continuous way and, on the other hand, an energy harvesting device, called air gene.
Air-gen, developed in 2020 by the same team of experts, is a thin film made of nanowires, which have been manufactured from the bacterium Geobacter sulphurreducens.
The device can collect energy from the environment, since its surface contains various napores (100 nanometers thick) that allow water vapor molecules to pass through and, inside, it generates the chemical conditions necessary to convert it into electricity.
Useful batteries for any scenario
According to scientists, the most interesting thing about Air-gen nanobatteries is that they could be designed from any material, which opens up endless possibilities.
“You could imagine energy harvesters made of one type of material for rainforest environments and another for more arid regions,” Yao says.
For now, University of Massachusetts engineers report, the Air-gen devices can power small electronics such as health monitors and smart watches. Its usefulness will soon be tested for cell phones.