Power-Generating Wallpaper Turns Indoor Humidity Into Electricity

For more than six million American households, the rooftop solar panel has become the familiar symbol of home-grown electricity. But a research team at Binghamton University is now asking a different question: what if the walls inside your house could generate power too? Professor Seokheun “Sean” Choi, a faculty member in the Thomas J. Watson College of Engineering and Applied Science’s Department of Electrical and Computer Engineering, and his students have designed a new type of wallpaper that harvests moisture from the air in a room and converts it into small amounts of electrical current. The work, published this month in the journal Advanced Energy Materials with PhD student Guangya “Roger” Yuan and Yang “Lexi” Gao, PhD ’26, as collaborators, points toward a future in which the very surfaces of a building quietly contribute to its energy supply.

The technology at the heart of the wallpaper is the moist-electric generator, or MEG. These devices absorb water molecules directly from the surrounding air. Once absorbed, the moisture promotes the dissociation and movement of ions within the material, establishing an ion-concentration gradient across the device. That gradient produces a separation of charge, which in turn establishes a voltage between the two sides of the generator. In practical terms, the wallpaper exploits one of the most ubiquitous and overlooked resources in any occupied building: the constant presence of water vapor released by breathing, cooking, and bathing. Rather than burning fuel or waiting for sunlight, the device draws its energy from the humidity that every home already produces around the clock.

Choi’s team deliberately positioned the technology away from the crowded field of high-energy power generation. The MEGs are not intended to compete with solar arrays, grid connections, or batteries in terms of raw output. Instead, they are designed to serve as dedicated power supplies for low-energy electronics: environmental sensors, wireless communications modules, smart-building interfaces, and the vast constellation of devices that make up the growing “Internet of Things.” These gadgets typically sip milliwatts or less, and wiring them all to mains power or servicing their batteries is one of the practical obstacles slowing the spread of distributed sensing. A wall covering that powers them continuously, without plugging in, could remove that obstacle entirely.

One of the most important insights behind the project is that indoor air, often dismissed as uninteresting from an energy standpoint, is actually a remarkably stable resource. “All previous moist electric-generator devices are for outdoor humidity, because there is a lot of moisture out there that is an excellent energy resource,” Choi said. “The problem is that it generates such small amounts of power, and the outdoor environment is not stable because of extreme sunlight or weather. The good thing about an indoor environment is that it maintains a very constant humidity between 30 and 60 percent, and the occupants’ activities like respiration, cooking, and bathing generate additional moisture.” That constancy matters enormously for a generator that depends on a steady flow of water vapor, because fluctuations in humidity translate directly into fluctuations in output.

Turning that insight into a product, however, required solving a genuine engineering problem. Most MEGs reported previously rely on vertical or horizontal structures with an asymmetric distribution of hygroscopic or ionizable materials. In such designs, one region preferentially absorbs moisture while another promotes desorption or evaporation, creating a sustained moisture and ion-concentration gradient that drives charge separation. The architecture works well at the scale of a laboratory sample. But when researchers attempt to scale it up to wall-sized arrays, two problems emerge: the design uses space inefficiently, and it becomes difficult to maintain directional moisture transport uniformly across a large area. A wallpaper that works in a one-square-centimeter patch is of little use if the same physics falls apart across an entire wall.

Choi’s solution draws on his earlier pioneering work in papertronics, the field of building electronic devices on paper substrates as biodegradable alternatives to traditional circuits. The new MEG architecture resembles a microchip laid out on a circuit board, but rendered in paper and printable materials. Glycerol positioned at the edges of each unit captures moisture from the air, while a raised polyvinylpyrrolidone, or PVP, structure in the center, patterned with a wax layer, controls moisture release and evaporation. This spatial arrangement directs moisture transport from the absorption region toward the evaporation region, maintaining a more controlled gradient for continuous power generation. In effect, each small patch of wallpaper behaves like an engineered micro-device rather than a simple slab of hygroscopic material.

Manufacturability was central to the design philosophy from the start. “It was not easy to integrate three different areas into one paper, but I want it all printable so that we can make it for mass production and at a larger scale,” Choi said. The emphasis on printing is what separates this work from many laboratory energy-harvesting demonstrations that never escape the cleanroom. If the absorption region, the evaporation-control region, and the ion-transport structure can all be deposited by printing processes on a paper substrate, the path to covering large wall areas at low cost becomes far more plausible than it would be for devices requiring delicate assembly. Paper-based electronics also carry potential advantages in sustainability, an area Choi’s group has explored in previous work on biodegradable circuits.

Aesthetics and practicality posed a second challenge that pure physics could not solve. Homeowners, the researchers recognized, would not tolerate a wall covered in visible wires and junctions. The team’s answer was to put all of the wiring for the MEG units on the back of the wallpaper, keeping the visible face clean and ordinary. The researchers then experimented with how the individual generators should be connected electrically, linking them in series and in parallel to determine which configuration produced the most power. Interestingly, both methods produced similar results, a finding that gives the designers useful flexibility in how future arrays are wired depending on the voltage and current requirements of the devices they are meant to supply.

Beyond generating electricity, the technology offers a second, perhaps unexpected benefit: humidity management. Buildings already spend enormous amounts of energy on heating, ventilation, and air-conditioning systems whose job includes removing excess moisture from indoor air. Because the wallpaper’s generators actively absorb and transport water vapor, installing them could help regulate a room’s humidity at the same time as they produce power. “We put a lot of energy into HVAC systems to remove moisture from the air, but if we use this concept, we could reduce or control moisture levels while also generating electricity,” Choi said. In that sense, the material performs double duty, offsetting a portion of the energy a building consumes while improving comfort.

For now, Choi sees the MEG arrays as best suited to powering small devices such as environmental sensors or wireless keyboards, and the team hopes to improve the technology for greater power yields in future iterations. Even at modest output levels, the implications are striking. The Internet of Things is projected to encompass billions of connected devices, many of them installed in buildings where batteries must be replaced and cables run at considerable expense. A power source that is printed onto paper, hidden behind ordinary wallpaper, fed by the humidity people generate simply by living in a space, and capable of simultaneously moderating that humidity, addresses several of those pain points at once. The Binghamton work suggests that the next wave of ambient energy harvesting may not come from the roof or the sky at all, but from the quiet, moisture-laden air between the walls we already live with.

Subject of Research: Indoor moisture-driven energy harvesting using moist-electric generator wallpaper

Article Title: Wallpaper that generates power? Binghamton University researchers have developed it

Article References: Wallpaper that generates power? Binghamton University researchers have developed it. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: moist-electric generators, energy harvesting, wallpaper, indoor humidity, Internet of Things, papertronics, Binghamton University, Advanced Energy Materials, sensors, smart buildings, humidity management, printable electronics