What just happened? Researchers from the University of Massachusetts Amherst believe it's possible to continually harvest electricity from humid air using nearly any material. The technique, which has been detailed in the journal Advanced Materials, has been likened to a man-made cloud.

Jun Yao, the paper's senior author, reminds us that air contains an enormous amount of energy. Yao points to a cloud, which is nothing more than a collection of water droplets that contain a charge. When conditions are right, the cloud can produce a huge amount of electricity in the form of a lightning bolt. Unfortunately, we don't have a reliable way to capture the electricity from lightning.

What Yao and the team propose is to essentially create a small-scale, human-made cloud that predictably and continuously produces electricity.

The breakthrough builds on previous work that Yao and a colleague competed in 2020 which demonstrated how to get electricity from the air using protein nanowires made of the bacterium Geobacter sulfurreducens.

After the Geobacter discovery, the team realized that nearly any material can be used to harvest electricity from the air so long as it has holes smaller than 100 nanometers. Hence, they're now calling the technique the generic Air-gen effect.

This harvester would be made from a thin layer of material filled with nanopores smaller than 100 nm that would let water molecules pass from the upper to the lower part of the material. But because each pore is so small, the water molecules would easily bump into the pore's edge as they pass through the thin layer. This means that the upper part of the layer would be bombarded with many more charge-carrying water molecules than the lower part, creating a charge imbalance, like that in a cloud, as the upper part increased its charge relative to the lower part. This would effectually create a battery – one that runs as long as there is any humidity in the air. – EurekAlert

This flexibility allows the harvester to be made from literally all kinds of materials, Yao said. Harvesters could be designed using the most cost-effective or environmentally-adaptable materials for a specific region. "You could image harvesters made of one kind of material for rainforest environments, and another for more arid regions," Yao added.

Because the technique relies solely on humidity, it could be run around the clock and regardless of factors like sunlight, rainfall, or wind strength. Each Air-gen device is also incredibly thin (a fraction of the width of a human hair), meaning many thousands could be stacked on top of each other to scale up the energy output without creating something with a massive footprint.

"We are opening up a wide door for harvesting clean electricity from thin air," said Xiaomeng Liu, the paper's lead author.

It all sounds great on paper but like virtually every other clean energy breakthrough, it's difficult to get too excited about until it is successfully demonstrated in the real world. Here's to hoping this actually graduates from the science lab and into reality someday.

Image credit: Andre Furtado