A flexible, foldable, tubular μDMFC for powering wrist bands

This paper reports a flexible tubular passive micro direct methanol fuel cell (μDMFC) for powering wrist bands at the first time. The tubular μDMFC, featured by flexible electrodes and foldable whole structure, shows excellent power density and long-term performance compared to batteries. The novelty claims of this work are: (1) a novel foldable structure and its fabrication, as well as assembly method proposed are usable for the flexible tubular μDMFCs and even other multi-layer flexible microfluidic devices; (2) the prototype achieves a power density of 15.3mWcm-2 and a maximum output of 38mW at room temperature; (3) the assembled μDMFC with a DC/DC converter is integrated into a wristband to power a LED and a DC motor (25mW) for about 20h with 1mL methanol. As such, it is believed that this μDMFC is applicable to serve as the power unit for wrist bands (typically 1~20mW) or even other wearable devices.