An Ion Pump Enhanced High‐Current‐Density Moisture‐electric Yarn

ABSTRACT Moisture‐electric generators (MEGs) offer a promising route for clean energy harvesting. However, most existing MEGs suffer from low current densities due to limited ion concentration and migration rates, while often lack of capability for direct integration of wearable systems. Here, a moisture‐electric yarn (MEY) featuring high current density and continuous power generation is designed. An ion pump strategy is introduced to facilitate the establishment of ion concentration gradients and enhance ion migration rates, enhancing electrical output. The MEY continuously generates ∼1 V and a high current density of 5.7 mA cm −3 at 25 °C and 60% RH, outperforming most reported MEGs. A scalable continuous fabrication process enables single‐batch production of hundreds of meters of yarn. Owing to its yarn structure, the output current increases with length, reaching 4.3 mA for a 1 m yarn (∼0.1 g). Harvesting atmospheric and body moisture, a 2 m MEY can sustainably power LED strips. This lightweight and sewable yarn provides a safe and eco‐friendly auxiliary power source for wearable electronics and real‐time positioning applications.