Using the same forces as lightning, the new technology extracts electricity from moisture

In a study published this week, scientists at the University of Massachusetts Amherst say they have created a device that can harvest electricity from moisture in the air.

The device, called Air-gen, is currently a fingernail-sized harvester made of a thin material with holes less than one-thousandth the width of a human hair – called nanopores – that generates electricity by allowing electrically charged water molecules in the air to go through. Using the same forces that create lightning, that movement through the membrane creates an electrical imbalance that produces electricity.

“Throughout history we have not been able to find any means of trapping electricity in the air.” That is dangerous. It is unpredictable. But I think this technology essentially makes that dream a reality,” said Jun Yao, assistant professor of electrical and computer engineering in the School of Engineering at UMass Amherst and senior author of the paper.

As of now, Air-gen can generate enough electricity to power a small sensor, such as a heart rate monitor, but the authors say the technology has the potential to be scaled up and used as a clean energy source that can help augment wind and solar. .

Perhaps the most significant discovery, the authors write in the journal Advanced Materials, is that any number of materials, including cellulose, found in plant cell walls, can be used for the device, provided it can be engineered with small enough pores. That could open the door to cheap mass production. Unlike batteries that require minerals such as lithium or solar panels that require silicon, mining would not be required, the researchers said.

The technology could be used for small personal tasks, such as charging mobile phones, and on a larger scale to help power the electricity grid when solar and wind power do not generate enough. They said the device was working ranging in humidity from 20 to 100 percent, noting that the Sahara desert has an average humidity of 25 percent. However, the higher the humidity, the higher the power output.

“Because air humidity is basically everywhere, we can constantly get electricity from the air,” Yao said. “I call it a sustainable, continuous and ubiquitous power solution.”

Some scientists welcomed the possibilities in what many saw as a new and innovative discovery. James Tur, a professor of chemistry and nanoengineering at Rice University in Texas, who was not involved in the study, called it remarkable and said it could have a “huge impact.”

“Its ease of use makes it super attractive,” he said.

Guihua Yu, a professor of materials science and mechanical engineering at the University of Texas at Austin, who was not involved in the study, called it a very new research paper that was technologically significant. “Sustainability is key,” he said.

But some scientists also said the scientific conclusions of the published work still don’t provide the kind of detail necessary to assess its practicality, especially on a large scale.

“It’s hard to know what to make of this,” said Donald Sadoway, professor emeritus of materials chemistry at the Massachusetts Institute of Technology. “It is not clear what practical numbers may emerge.” Investors would ask what we can expect in terms of wattage output and price.

He noted that one of the materials used in the current device is gold.

“It’s not good from a cost standpoint,” he said.

The discovery builds on earlier discoveries, including by Yao’s, that showed the idea of ​​making electricity from moisture could work, but only in limited situations — with a certain material or in specific situations, such as when the device is exhaled. In their latest paper, Yao and his co-authors describe a technology with many possible uses.

The authors envision scaling to deliver kilowatt-level power for general electricity use—enough to meet household demand. The extremely thin devices can be stacked vertically, they write, increasing the amount of energy produced while maintaining a relatively small footprint.

Sorin Grama, chief executive of Transaera, a clean energy startup working to improve air conditioning, said he had a hard time envisioning Air-gen competing with wind or solar, which have already scaled up, but said he could see he finds his place in the market. “It could find its niche perhaps in lower power devices,” he said.

In the meantime, the authors hope to see the technology take off.

“We are kind of chasing the concept of energy sustainability,” Yao said. “What I imagine is that sometime in the future we will be able to get clean electricity wherever we go.”

Sabrina Shankman can be reached at sabrina.shankman@globe.com. Follow her on Twitter @shankman.