When it comes to renewable energy, many cities combine multiple sources, such as solar panels and wind turbines. Scientists have now taken a similar approach with a "smart" shirt that generates electricity via both sweat and movement.
Created by a team at the University of California-San Diego, the "wearable microgrid" shirt incorporates sweat-powered biofuel cells, motion-powered triboelectric generators, and supercapacitors for storing the generated electricity.
All of the parts are screen-printed onto the fabric, including the waterproofed silver circuitry that connects them. Importantly, everything is flexible, stretchable, foldable and washable – that said, in the technology's current form, detergent cannot be used.
Located inside the shirt at chest level, the biofuel cells contain enzymes which trigger a swapping of electrons between the lactate and oxygen molecules present in human sweat. This process produces a continuous low-voltage electric current, which is fed into the capacitor for storage.
The triboelectric generators, meanwhile, each consist of two pieces of material: a negatively charged piece on the inside of the forearm, and a positively charged piece on the side of the torso. As the wearer's arms swing while they're walking or running, those pieces of material rub against one another. Doing so generates pulses of high-voltage electricity, which likewise goes into the capacitor.
In tests conducted so far, a volunteer wore the shirt while either running or using an exercise bike for 10 minutes, after which they rested for 20 minutes. For the entirety of each 30-minute session, the wearable microgrid was able to power either an LCD wristwatch or a small electrochromic display.
Once developed further, the present version of the shirt could be used by athletes for powering devices such as performance-monitoring sensors. Down the road, however, it could be equipped with different types of energy harvesters, and used by people who are sitting in an office or walking about slowly.
A paper on the research, which is being led by Prof. Joseph Wang and PhD student Lu Yin, was recently published in the journal Nature Communications.
The wearable microgrid is demonstrated in the following video.
Source: University of California-San Diego