Energy Harvesting‐Storage Bracelet Incorporating Electrochemical Microsupercapacitors Self‐Charged from a Single Hand Gesture

Abstract The development of wearable electronics and sensing networks has increased the demand for wearable power modules that have steady output, high energy density, and long cycle life. Current power modules, such as batteries, suffer from low energy density due to their limited storage capacity. One solution to avoid the issue is to build a hybrid device consisting of both energy harvesting elements that continuously harvest ambient mechanical energy, and electrochemical energy storage units to store the harvested energy. Here, a hybrid energy harvesting bracelet, which combines a dual electromagnetic and triboelectric nanogenerator to harvest wrist motions, is reported. The bracelet is able to charge the RuO 2 ‐based microsupercapacitor to 2 V with a single shake of human wrist, which allows the supercapacitor to power most electronic devices for minutes, such as a calculator, relative humidity, and temperature sensors.