Science Daily August 17, 2022
The current moisture-driven energy generation (MEG) materials and devices only establish moisture-driven energy interaction during water sorption in specific configurations, and conversion is eventually ceased by saturated water uptake. Researchers in Singapore have developed an asymmetric hygroscopic structure (AHS) that simultaneously achieves energy harvesting and storage from moisture absorption. The AHS was constructed by the asymmetric deposition of a hygroscopic ionic hydrogel over a layer of functionalized carbon. Water absorbed from the air creates wet-dry asymmetry across the AHS and hence an in-plane electric field. The asymmetry could be perpetually maintained even after saturated water absorption. The absorbed water triggered the spontaneous development of an electrical double layer (EDL) over the carbon surface (termed a hygro-ionic process), accounting for the capacitive properties of the AHS. A peak power density of 70 µW cm-3 was realized after geometry optimization. The AHS showed the ability to recharge by itself. In addition to insights into moisture-material interaction, AHSs further showed potential for electronics powering in assembled devices…read more. TECHNICAL ARTICLEÂ