Energy autonomous hybrid electronic skin with multi-modal sensing capabilities

As wearable devices to mimic the sensing capabilities of human skin, electronic skins with practical concerns of functionality and comfort start to take center stage. The heavy and bulky batteries in early designs pose flexibility and miniaturization issues. It is therefore highly desirable to develop a battery-free flexible electronic skin for multiple motion sensing. To that end, we have designed a self-powered hybrid electronic skin (HES) combining triboelectric (TB) and piezoelectric (PZ) effects to realize a wearable multi-sensing. Pressure sensitivity approaches 54.37 mV kPa(-1) and 9.80 mV kPa(-1) in the pressure range of 0-80 kPa and 80-240 kPa, respectively. The fabricated HES demonstrates excellent durability even after 14,000 periodic operation cycles. Additionally, it can measure and differentiate contact and non-contact sensing, such as click sensing, distance distinguishing, respiration detection, head motion sensing, and vocal cord vibration recognition, along with some physiological signals monitoring. As an assembled sensor array, the HES distinguishes multi-point pressure distribution and realize single-point touch trajectory visualization in real-time. In the near future, this HES could represent a critical component in smart robots, intelligent prostheses, and healthcare monitoring.