Engineers at the University of California, San Diego have developed what they claim is by far the most powerful wearable fuel cells that run on sweat and produce enough electricity to energize small components such as LEDs and Bluetooth radios.
The stretchable devices stick to the skin and conform to its movements, maintaining the ability to generate electricity with a voltage of .5 V and a power density of 1.2 mW cm−2 at 0.2 V. A person riding a standing exercise bike was able to light up an LED from a small patch stuck to the skin, while in a lab test the device was subjected to strains of 50% for two days without diminishing in performance.
The technology required coming up with a way to screen-print cathode and anode arrays made of carbon nanotubes and creating a biofuel cell featuring a lactic acid-oxidizing enzyme that produces electricity from sweat. The cathodes and anodes are numbered in the dozens, each connected to the rest of the system via flexible gold spring-like structures. These connections are made using lithography and the actual biofuel cell attached to the back of this structure.
Study in Energy & Environmental Science: Soft, stretchable, high power density electronic skin-based biofuel cells for scavenging energy from human sweat…
Via: UC San Diego…