A New Wallpaper Harvests Electricity From the Humid Air Inside Your Home

The paper wall covering powered a wireless keyboard while soaking up excess humidity.

A wall, in most rooms, just sits there. That’s usually just fine. But researchers at Binghamton University want it to do a little more work.

They have built a paper-based “moist-electric” wallpaper that pulls water vapor from indoor air and uses the resulting movement of charged particles to generate a small but steady current. In an experiment, a panel made from 1,596 tiny generator units powered a wireless keyboard at about 38 percent relative humidity. The same panel reduced humidity measured nearby from roughly 38 percent to 32 percent in 15 minutes.

The electricity produced by the device, described in Advanced Energy Materials, can’t compete with something like a solar panel. But that’s not really the point. The idea is to generate an extra bit of power that would normally go to waste, which can then be used to power sensors, wireless devices and other electronics that don’t need a lot of power.

Keeping water on the move

Moisture-electric generators (MEG) aren’t new. A 2015 graphene oxide study showed that a chemical gradient is enough to generate electricity from humidity. In 2020, researchers reported in Nature that protein nanowires made by bacteria could maintain a moisture gradient and produce continuous power. A 2023 Joule study later demonstrated fully printed arrays of planar moisture generators.

The problem is that most moisture-powered materials eventually get uniformly damp. Once that happens, there is no longer a wetter side and a drier side to push charged particles in one direction, so the electrical current dwindles and eventually stops.

The Binghamton team tried to prevent that by giving water a defined entrance and exit. Each generator is a 2-by-2-centimeter square of thick chromatography paper. Glycerol around the edges readily absorbs water vapor. Farther inward, a polymer called polyvinylpyrrolidone, or PVP, holds water more tightly and narrows the spaces between paper fibers. The setup now pulls liquid toward the center.

There, wax changes the rules. Wax-treated pores repel liquid water but remain open enough for vapor to escape. Moisture therefore enters around the perimeter, moves inward as liquid and leaves through the center as vapor. That one-way traffic keeps the paper from simply becoming uniformly damp.

The researchers propose that water interacting with oxygen-rich chemical groups releases mobile hydrogen ions, creating a charge imbalance that drives current. But they have not yet directly confirmed that protons carry most of it.

Enough to power a keyboard

At 80 percent humidity, one unit produced about 0.34 volts and a peak power density of 2.2 microwatts per square centimeter of electrode. Across the full square, the more relevant figure is about 0.55 microwatts per square centimeter.

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Covering the glycerol intake drove voltage close to zero. Covering the wax center allowed some power at first, but output declined as the paper filled with water. With both pathways open, voltage remained steady through roughly 270 minutes of testing.

In a small scaling test, 10 generator units wired in series produced about 3 volts at 80 percent humidity. The researchers then built a much larger wall panel containing 1,596 units, arranged in a series-parallel network. At about 38 percent humidity, the panel produced roughly 3.5 volts and, with help from a capacitor that stored charge for brief spikes in demand, powered a wireless keyboard in real time. The 1,596-unit wall showed that a much larger array could provide both the voltage and enough current to run a real device.

A 2024 Nature Reviews Materials perspective on sustainable moisture energy described the field as promising but highlighted low energy productivity and lingering uncertainty about its mechanisms.

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But don’t start redecorating just yet. The prototype uses laboratory chromatography paper, whose durability over years is unknown, and glycerol may migrate inward over days or weeks and blur the carefully engineered zones.

The humidity-control result is preliminary, too. The room-scale measurement lasted only 15 minutes. In a sealed chamber, however, 28 units lowered relative humidity from about 75 percent to 50 percent in roughly four minutes.