A sweaty aerobic workout not only keeps you fit but it could also power your phone.
Researchers from the University of California in San Diego have unveiled a temporary tattoo that can power gadgets based on how much you sweat.
The biobattery is powered by lactate – which is naturally present in sweat after heavy workout. It could soon power heart monitors, digital watches and eventually even smartphones, say scientists in California.
Some harness movement – via piezoelectric – while others use blood to power implanted biofuel cells.
“Our device is the first to use sweat. It’s a proof of concept,” said Dr Wenzhao Jia of at the University of California, San Diego, who gave details of her method in the journal Angewandte Chemie.
“At the moment the power is not that high – only four microwatts. But we are working on enhancing it so it can power small electronic devices.”
Athletes in training measure their lactate levels to evaluate their work-rate and fitness.
But monitoring it can be inconvenient as it involves collecting blood samples.
To make monitoring more comfortable, Dr. Jia printed a lactate sensor onto temporary tattoo paper.
“It’s not just for athletes. Most people who exercise want to know how they can improve their workout.
“We can measure our heart rate – but if you combine that physical feedback with chemical data you get a much more comprehensive view of your exercise status.” She said.
The next step involves removing electrons from lactate. This made the team realize that they had created one half of a battery cell. “We came up with this idea of harvesting energy from the body in a non-invasive manner,” says UC nanoengineering professor Dr. Joseph Wang in a new video about the research. All they needed to do was add a cathode. “In this case, the anode contained the enzyme that removes electrons from lactate, and the cathode contained a molecule that accepts the electrons,” explains PhysOrg.
When people on a gymn bike wore the tattoo, they were found to produce up to 70 microwatts per sq cm of skin.
Interestingly, people who were not healthy generated more power. While those who work out more generated the least.
“We think that’s because less fit people become fatigued sooner, so they form more lactate,” Dr Jia explained.
“A fit person is going to have to work out much harder to power the battery.”
Her team has collaborated with a start-up company to develop the product.
Finally, the tattoos are linked to portable gadgets, and adding a way to store the produced power- by integrating a device such as capacitor.
But the main challenge is to increase the power. More than double the current value would be required for a digital watch – 10 microwatts.
One possibility is to make the device more sensitive to lactate. Another is to add some more biofuel cells – connected in serial or parallel.
But why use the body at all? Why not simply miniaturize conventional batteries and make them wearable?
“Because biobatteries offer certain other advantages,” explained Dr Jia.
“They recharge more quickly. They are safer as there is no risk they will explode or leak toxic chemicals.
“And they use a renewable energy source. Your body.”
Via : gizmodo