American engineers have designed a bio-enzymatic fuel cell of reduced size. Placed on the fingertips, it can generate enough electricity to power some small appliances. According to officials, these could be electronic watches or even medical sensors.
A pile of lactic acid from our sweat
And if the energy is needed to control small appliances electricity could come from our fingertips? Researchers from the University of California, San Diego (USA) have developed a bioenzymatic fuel cell, details of which appear in a publication in the journal joule from July 13, 2021. At your fingertips, the battery in question converts perspiration into electricity.
Keep in mind, however, that this battery is not the first to convert sweat into electrical current. Indeed, other bioenzymatic fuel cells already exist, in the form of insoles (or fabric). However, the stack of American engineers didn’t no physical activity required to work. So the latter can even work while we sleep!
Specifically, it is a thin strip to be placed on the fingertips, consisting of: carbon foam electrodes. The electrodes absorb sweat before enzymes cause a chemical reaction. For example, the reaction between lactic acid in sweat and oxygen produces electricity.
“We envision that this device can be used during any day-to-day activity that involves touch, activities that a person would normally do, such as at work, at home, while watching television, or even while eating. The goal is for this wearable to work naturally without you having to think about it” Joseph Wang, a nanoengineering expert and lead lead at work, said in a statement.
A small amount of energy
According to the engineers, the choice within reach is no accident. Indeed, this part of the fingers contains about a thousand sweat glands. That’s how it produces between 100 and 1,000 times more sweat than most other parts of the body. Furthermore, the bioenzymatic cell contains a layer of piezoelectric material. However, the latter generates electricity after each finger press. We also call the presence of a capacitor to store the produced energy.
As mentioned above, the battery can also work during sleep. During a ten-hour night, the device is able to about 400 millijoules of energy. Note that by placing a battery on several fingers, it is possible to multiply the amount of energy. Still, this energy is enough to power a simple electronic watch for an entire day.
Obviously, this energy is not enough to power a connected watch, much less a smartphone. On the other hand, technology could make it possible to operating small medical sensors and could therefore find application in the fields of health and sport.
Here is the demonstration of this famous bioenzymatic fuel cell: