UNIST researchers develop ultra-small moisture generator

Researchers at UNIST have developed an ultra-small, thin-film moisture generator capable of producing electricity for up to 45 hours using only 3 microliters of water. Led by Professor Koh Hyun-hyup, the team designed a device smaller than a fingernail that utilizes the concentration difference of cations within water to generate direct current.

The device features a nanochannel structure made of MXene and cellulose nanofibers. As water moves through the narrowing channels via capillary action, the attraction from the channel walls creates a concentration gradient of cations, inducing voltage. Unlike previous moisture generators that relied on evaporation or humidity—making them sensitive to environmental changes—this design minimizes external influence by inducing selective ion movement through its internal structure.

The thin, flexible film can be stacked in multiple layers to increase power output. The research team successfully powered a digital clock by connecting 48 units in series. The technology has demonstrated the ability to generate power from various liquids, including tap water, seawater, and even sweat, offering significant potential for wearable electronics, small sensors, and distributed power sources.