Breathable and Stretchable Multifunctional Triboelectric Liquid‐Metal E‐Skin for Recovering Electromagnetic Pollution, Extracting Biomechanical Energy, and as Whole‐Body Epidermal Self‐Powered Sensors

On‐skin electronics can be conformably deployed on body for health monitoring, assisted living, and human/computer interfaces. However, developing corresponding energy devices is a critical challenge. Herein, a permeable and stretchable multifunctional liquid‐metal electronic skin that can generate electricity by recovering ambient electromagnetic pollution (from surrounding electrical appliances) and biomechanical energy (from body movements) is presented for epidermal energy and self‐powered sensing applications. To the best of the authors' knowledge, this is the first demonstration that a breathable on‐skin device can convert ambient electromagnetic pollution into useful electricity. The device is constructed using two stretchable microfibrous films sandwiching self‐organized mesh‐like and wrinkled liquid‐metal that affords electricity via induced electrification (±9.3 V, ±1.7 µA; 60 Hz) and triboelectricity (205.6 V, ±2.3 µA; 4 Hz). Its applicability in powering electronic devices is demonstrated. Moreover, it can serve as an epidermal self‐powered sensor for continuously monitoring whole‐body physiological signals and motions of the eyelids, face, throat, chest, and limbs, thus demonstrating its potential to remotely collect clinical and biomechanical information. Finally, it is used as an interface in diverse system‐level applications. These results shed light on new directions in on‐skin energy and sensing, enabling to usher electronics toward untethered and diversified applications. A breathable and stretchable multifunctional liquid‐metal fibrous electronic skin is proposed for producing electricity by converting ambient electromagnetic pollution (from surrounding electrical appliances) and biomechanical energy (from body movements), serving as an epidermal energy source and whole‐body self‐powered sensors and interfaces. These findings suggest new possibilities for the use of on‐skin energy.