What if the humidity in the air around you could charge your fitness tracker or power your smart home sensors? That is exactly what an international research team led by scientists at Queen Mary University of London has achieved.
Their new device, called a Moisture-Electric Generator or MEG, turns ambient moisture into usable electricity using just three ingredients you could find in any kitchen: gelatin, table salt, and activated charcoal.
How does it work?
The MEG works by absorbing water molecules from the surrounding air or directly from human skin. When the gelatin and salt mixture dries, it naturally separates into three distinct layers without any complex manufacturing steps.
This structure creates a moisture gradient that drives ion movement through the material, generating a stable electrical output of around 1 volt per unit for over 30 days.
When you connect 100 units together in a series, the output scales up to 90 volts and 5.08 milliamps, enough to power a string of 40 decorative lights. That 100-unit stack also weighs just 6.7 grams and takes up less space than a standard AA battery, which only delivers 1.5 volts by comparison.
It can sense your breathing and dissolve in soil when you are done with it
Beyond generating power, the MEG doubles as a self-powered sensor. It can detect breathing patterns in real time by picking up changes in exhaled moisture. It can also read the number of syllables in spoken words and track skin hydration levels.
Even touchless proximity sensing is possible, since natural moisture from a hovering fingertip is enough to trigger a voltage response. The best part is that the device biodegrades in soil within three weeks and can be recycled by dissolving it in water and recasting it, with no loss in performance.
The MEG joins a growing list of battery-free energy ideas. Researchers have previously demonstrated a protein nanowire device that harvests electricity from air moisture, a bionic mushroom that generates power through bacteria, and near-invisible solar cells thin enough to coat a car window.