The integration of electronic systems into flexible, wearable devices has potential applications in medical care and consumer electronics. One bottleneck of such technologies is to develop flexible power sources. Current consumer electronics usually use rechargeable lithium ion batteries as the power source. The batteries are rigid, bulky, heavy and not compatible with all-flexible electronics. The batteries also have safety issues such as being flammable and explosive. Electrochemical supercapacitors are energy storage devices that store energy by electrochemical double layer effect and/or redox reaction based pseudo capacitance effect. They store about one order less energy per weight compared to lithium ion batteries, but they can be rapidly recharged in seconds/minutes, survive more than 100,000 charge-discharge cycles, and operate safely. Researchers at UC Berkeley have developed an approach to make supercapacitors in the form of flexible fabrics to power flexible, wearable electronics. The supercapacitors may be woven into flexible fabrics, which can function as portable or wearable energy sources. Alternatively, they may be made strong and stiff, which can then be used as structural components in electrical vehicle, drones, satellites, and so on, to provide mechanical support and energy at the same time.