It turns out that literally any material can generate electricity from air.

But “It needs to have holes smaller than 100 nanometers (nm), or less than a thousandth of the width of a human hair.”

A team of engineers from the University of Massachusetts Amherst has unveiled a groundbreaking discovery known as the “generic Air-gen effect.”

This remarkable phenomenon allows for the transformation of various materials into efficient, cost-effective, and scalable electricity generators that operate seamlessly without interruptions.

Their pioneering research, published in the esteemed journal Advanced Materials, reveals that the key to this breakthrough lies in the strategic integration of nanopores, each measuring less than 100 nanometers, throughout the material. These nanopores enable the continuous extraction of electrical energy from atmospheric humidity.

“This is very exciting,” comments lead author Xiaomeng Liu. “We are opening up a wide door for harvesting clean electricity from thin air.”

“The air contains an enormous amount of electricity,” explains senior author Jun Yao. “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 a lightning bolt—but we don’t know how to reliably capture electricity from lightning. What we’ve done is to create a human-built, small-scale cloud that produces electricity for us predictably and continuously so that we can harvest it.”

The core of the artificial cloud relies on what Yao and his team refer to as the “generic Air-gen effect.” This groundbreaking development builds upon the earlier research conducted by Yao and his co-author, Derek Lovley, an esteemed Microbiology Professor at UMass Amherst. In their prior study in 2020, they successfully demonstrated the consistent extraction of electricity from the atmosphere by utilizing a unique material composed of protein nanowires cultivated from the bacterium Geobacter sulfurreducens.

“What we realized after making the Geobacter discovery,” adds Yao, “is that the ability to generate electricity from the air—what we then called the ‘Air-gen effect’—turns out to be generic: literally any kind of material can harvest electricity from air, as long as it has a certain property.”

Centain property?

“It needs to have holes smaller than 100 nanometers (nm), or less than a thousandth of the width of a human hair.”

This phenomenon can be attributed to a parameter known as the “mean free path,” which represents the distance traveled by an individual molecule of a particular substance, such as water in the air, before colliding with another molecule of the same substance. In the case of suspended water molecules in the air, their mean free path measures approximately 100 nm.

Yao and his colleagues recognized the potential of harnessing this characteristic to develop an electricity harvesting device. Their concept involved constructing a thin layer consisting of nanopores smaller than 100 nm, allowing water molecules to traverse from the upper to the lower region of the material. Due to the minuscule size of each pore, the water molecules encounter the edges of the pores as they pass through the thin layer. Consequently, the upper portion of the layer experiences a greater influx of charge-carrying water molecules compared to the lower part. This charge imbalance, similar to that found in a cloud, results in an effective battery-like system. It operates continuously as long as there is humidity present in the air.

“The idea is simple,” remarks Yao, “but it’s never been discovered before, and it opens all kinds of possibilities.”

The harvester has the potential to be constructed using a wide variety of materials, providing extensive options for economically viable and environmentally adaptable manufacturing processes.

“You could image harvesters made of one kind of material for rainforest environments, and another for more arid regions.”

Due to the constant presence of humidity, the harvester operates continuously, regardless of weather conditions or time of day. This feature addresses a significant challenge faced by technologies like wind or solar, which rely on specific conditions for optimal performance.

Moreover, the Air-gen device takes advantage of the three-dimensional diffusion of air humidity. With a thickness equivalent to only a fraction of a human hair, multiple units can be stacked on top of each other, significantly increasing the energy output without requiring additional space. As a result, this innovative Air-gen device has the potential to deliver kilowatt-level power for various electrical utility applications, while maintaining a minimal footprint.

“Imagine a future world in which clean electricity is available anywhere you go,” adds Yao. “The generic Air-gen effect means that this future world can become a reality.”

Source: 10.1002/adma.202300748

Image Credit: Getty