The research, published in a paper in Advanced Materials, builds on 2020 work that first showed energy could be pulled from the moisture in the air using material harvested from bacteria. The new study shows that nearly any material can be used, like wood or silicon, if it can be smashed into small particles and remade with microscopic pores.
The air-powered generator, known as an "Air-gen", would offer continuous clean electricity since it uses the energy from humidity, which is always present, rather than depending on the sun or wind.
The device, the size of a fingernail and thinner than a single hair, is dotted with tiny holes known as nanopores. The holes have a diameter smaller than 100 nanometers.
UMass engineering graduate student Xiaomeng Liu said that the tiny holes allow the water in the air to pass through in a way that would create a charge imbalance in the upper and lower parts of the device, effectively creating a battery that runs continuously.
While one prototype only produces a small amount of energy — almost enough to power a dot of light on a big screen — because of its size Air-gens can be stacked on top of each other, potentially with spaces of air in between.
Storing the electricity is a separate issue. Apparently a billion Air-gens, stacked to be roughly the size of a refrigerator, could produce a kilowatt and partly power a home in ideal conditions.
The team hopes to lower both the number of devices needed and the space they take up by making the tool more efficient.
It could be embedded in wall paint in a home, made at a larger scale in unused space in a city or littered throughout an office's hard-to-get-to spaces.
And because it can use nearly any material, it can extract less from the environment than other renewable forms of energy.
"The entire earth is covered with a thick layer of humidity. It's an enormous source of clean energy. This is just the beginning in making use of that," he said.