Humidity nanogenerators produce continuous power

Queen Mary University of London researchers said on May 21 that they had built a moisture-electric generator that draws power from humidity in the air and from skin, using gelatin, sodium chloride and activated carbon rather than conventional battery materials. The device, described in a university release tied to a paper in *Nano Energy*, is biodegradable and made through a water-based process. The team said the generator produced a continuous electrical output without moving parts. The work adds to a growing field of “moisture electricity” devices that try to turn atmospheric water into low-power energy for sensors and wearables. ### What exactly did the researchers build? The Queen Mary-led team called the device a Moisture-Electric Generator, or MEG. According to the university and EurekAlert releases, it is made from food-grade gelatin, table salt and activated carbon, and it forms a three-layer structure as the gelatin-salt mixture dries. (qmul.ac.uk) Dr. Ming Dong, a postdoctoral research associate at Queen Mary and the study’s first author, said the device uses “ambient humidity as its sole energy source.” The university said water molecules absorbed from surrounding air or human skin enable ion movement inside the material, which creates the electrical output. (qmul.ac.uk) ### How much power did it produce? The university said each unit generated about 1 volt continuously for more than 30 days under humid conditions. In a scaled demonstration, the researchers connected units in series and reached as much as 90 volts and 5.08 milliamps, enough to power a 40-light LED string. (qmul.ac.uk) The demonstration matters because moisture-electric devices have often struggled to sustain output over long periods or to reach useful voltages. A 2024 *Nature Communications* paper on moisture-based energy harvesting, for example, reported generation lasting 600 hours, underscoring that durability has become a central benchmark in the field. ### Why use gelatin, salt and activated carbon? (qmul.ac.uk) The Queen Mary release said the materials were chosen because they are widely available, non-toxic and compatible with a simple water-based manufacturing process. The researchers framed that as a possible alternative to more complex energy-harvesting systems and to battery chemistries that add to electronic waste. (nature.com) Dr. Ming Dong said high voltages usually require “complex manufacturing processes or scarce materials,” and said the project showed “strong performance” from simpler components. The team included researchers from Queen Mary, the University of Warwick, Imperial College London and Universitas Mercatorum. (qmul.ac.uk) ### Where could this be used first? Queen Mary said the material could serve both as a power source and as a humidity-sensitive, skin-compatible sensor. Because the output changes with moisture levels, the team said it could detect physiological signals linked to humidity variation, which points to wearable health devices and low-power remote sensors as early targets. (qmul.ac.uk) A recent review in *Nature Reviews Materials* said moisture-sorption energy harvesting is being studied for electricity generation “anywhere and anytime,” particularly where low-power, distributed electronics need continuous trickle energy. That broader literature helps place the Queen Mary device in the sensor and Internet-of-Things category rather than as a replacement for high-capacity batteries. (qmul.ac.uk) ### What comes next? The paper is published in *Nano Energy*, according to Queen Mary and ScienceDirect indexing, and the next step will be outside validation of the device’s performance and durability under varied humidity and real-world wear conditions. The named participants are Queen Mary University of London, the University of Warwick, Imperial College London and Universitas Mercatorum. (qmul.ac.uk) (nature.com)