Interfacial ion-electron conversion enhanced moisture energy harvester

Harvesting energy from the surrounding environment holds great promise for meeting decentralized energy demands and facilitating the transition to a low-carbon economy. Ubiquitous moisture in the air offers a natural energy reservoir, but very little has yet been harnessed. Conventional moisture-electricity generators collect moisture energy through the directional migration of ions in the moisture-sorption functional materials induced by a moisture field. However, the unsatisfactory output performance severely limits their practical implementation. Herein, we develop an ion-electron conversion enhanced moisture energy harvester (i-eMEH) by creating an ion-enriched storage interface and concurrently inducing a faradic process through the dual redox couples in the functional layer/electrode interfaces. The i-eMEH reaches a record-high peak current of 9.2 mA cm−2 and power density of 6.7 W m−2, ~60 times higher than those of reported moisture-electricity generators, and approaching the output level of perovskite solar cells and thermoelectric devices. The output rises to hundreds of milliamperes and tens of volts through the device enlargement and integration, thus efficiently charging the capacitor (4F) and commercial lithium battery. This moisture energy harvester manifests the great potential for miniaturized flexible electronics and presents a crucial step towards practical applications of moisture energy harvest.