Printed wallpaper harvests indoor humidity to power small electronics

More than 6 million homes in the United States carry solar panels on their roofs. Researchers at Binghamton University are now looking at generating power inside the house as well, with a new type of wallpaper that turns moisture in a room into small amounts of electric current. They hope to improve the technology to raise its power yield.

Professor Seokheun "Sean" Choi, a faculty member in the Department of Electrical and Computer Engineering at the Thomas J. Watson College of Engineering and Applied Science, led the research, published this month in the journal Advanced Energy Materials. PhD student Guangya "Roger" Yuan and Yang "Lexi" Gao, who completed a PhD in 2026, collaborated on the study.

The wallpaper uses tiny moist-electric generators (MEGs) that absorb water molecules from the air. The absorbed moisture promotes the dissociation and movement of ions within the material, creating an ion-concentration gradient. That charge separation sets up a voltage between the two sides of the device, allowing electrical energy to be generated.

The MEGs are not meant to compete with high-energy power sources. They can instead act as dedicated supplies for low-energy electronics such as environmental sensors, wireless communications modules, smart-building interfaces and other data-collecting devices in the growing Internet of Things.

Choi said all previous moist-electric generator devices were designed for outdoor humidity, because the large amount of moisture outdoors is an excellent energy resource. The difficulty, he said, is that they generate very small amounts of power and the outdoor environment is unstable because of extreme sunlight or weather. Indoors, he said, humidity stays fairly constant at between 30 and 60 percent, and occupants add moisture through breathing, cooking and bathing.

No indoor-compatible design had combined the necessary technology with the appearance a homeowner would expect, so the Binghamton team had to overcome several challenges.

The most common MEGs use vertical or horizontal structures with an asymmetric distribution of hygroscopic or ionizable materials. One region preferentially absorbs moisture while another promotes desorption or evaporation, creating a sustained moisture and ion-concentration gradient that drives charge separation. Scaling that architecture to wall-sized arrays, however, can use space inefficiently and make it hard to maintain directional moisture transport over large areas.

To get around those limits, the researchers drew on Choi's earlier work in papertronics to develop a new MEG architecture that resembles a microchip on a circuit board. Glycerol at the edges captures moisture from the air, while a raised polyvinylpyrrolidone (PVP) structure in the center, patterned with a wax layer, controls moisture release and evaporation. The layout directs moisture from the absorption region toward the evaporation region, maintaining a more controlled gradient for continuous power generation.

Choi said integrating three different areas into one sheet of paper was not easy, but he wants the whole device to be printable so it can be mass produced at larger scale.

Because homeowners would not want to see wires, a second design feature places all the wiring for the MEGs on the back of the wallpaper. The researchers connected the generators in series and in parallel to see which arrangement produced more power, and found both gave similar results.

For now Choi sees the MEG arrays as a way to power small devices such as environmental sensors or wireless keyboards while also regulating a room's humidity.

He said a great deal of energy goes into HVAC systems to remove moisture from the air, and that this concept could reduce or control moisture levels while generating electricity at the same time.

CONTACT: https://advanced.onlinelibrary.wiley.com/doi/10.1002/aenm.71603