A Self‐Powered, Shapeable, and Wearable Sensor for Effective Hazard Prevention and Biomechanical Monitoring

ABSTRACT Flexible and wearable electronics are attracting surging attention due to their potential applications in human health monitoring and precision therapies. Safety hazards including strong magnetic field and electric leakage are big risk factors for human health. It remains challenging to develop self‐powered and wearable safety hazard sensors that could not only be able to monitor human motions but also have functions for detecting potential hazards. In this work, we fabricated a self‐powered, shapeable, and wearable magnetic triboelectric nanogenerator (MTENG) based on ferrofluid, Ecoflex, and carbonized silk fabric that possessed effective hazard prevention and biomechanical motion sensing ability. A peak open‐circuit voltage of 0.7 V and short‐circuit current of 10 μA m −2 can be achieved when magnetic field is changed between 3.5 and 37.1 mT. As a component of triboelectric layer of the MTENG, ferrofluid can substantially extend the range of its sensing capabilities to many hazardous cues such as dangerous magnetic field. Furtherly, the developed multifunctional and self‐powered sensor can be used to monitor human activities such as drinking water and bending finger. This effort opens up a new design opportunity for hazard avoidance wearable electronics and self‐powered sensors.