An Oryza Sativa Leaves‐Inspired Moisture Electric Generator for Self‐Powered Wearable Sensing and Communication Underwater

ABSTRACT Environmental moisture is an abundant, renewable energy source that enables the operation of humidity‐driven power generation devices. However, moisture electric generators (MEGs) struggle to operate underwater because of the instability of hygroscopic material and the flooding screening of charges in the aquatic environment. Inspired by the gas film strategy of Oryza sativa leaves, we develop a moisture‐driven self‐powered device based on a waterproof breathable membrane so that our device can “breathe” even under full immersion while protecting internal components from water. The single device outputs 0.66 V and ∼25 µA under a liquid water environment. By introducing a porous raised‐rim structure, the MEG shows high sensitivity to mechanical pressing due to the tunable contact at the interface between electrode and hygroscopic layer, enabling a wide pressure‐detection range (1.40 ∼ 70.19 kPa), high sensitivity (0.39 kPa −1 ), and fast response (300 ms). Based on this coupling, the device can detect respiration and support underwater Morse‐code communication. By introducing a spacer layer, the device can freely bend and accurately recognize aquatic motion. This study breaks the dependence of MEGs on atmospheric conditions and broadens their functionality from energy harvesting to multimodal sensing, revealing strong potential for underwater wearable and intelligent sensing applications.