Electric eels inspired an international team of researchers to develop soft power cells that could one day run pacemakers, health monitors, or one day even augmented-reality contact lenses. Their power source – which Smithsonian.com described as a foldable battery – can generate around 110 volts. Although that’s far less than an eel could produce, the researchers say their work could offer important insight into soft power sources.
Electric eels can deliver a shock strong enough to knock a horse right off its feet, according to Smithsonian.com. This new soft power source isn’t that strong – but it could pave the way for powering devices without the concerns over toxicity or size associated with common batteries. University of Michigan, Adolphe Merkle Institute at the University of Fribourg, and University of California, San Diego researchers developed the power cell that “moves charged ions across a selective membrane to produce power.”
The team made their foldable battery by printing different kinds of drops – composed of sodium and chloride dissolved in water-based hydrogel – on sheets. One sheet has salty and pure water drops alternating, while the other has charge-selective hydrogels, allowing “either positively charged sodium or negatively charged chloride to pass, excluding the other.”
Pressing the sheets together generates power by connecting “saline and freshwater droplets across the charge-selective droplets in series. As the salty and fresh solutions mix, the charge-selective droplets move the sodium and chloride ions in opposing directions, producing an electric current.”
The team improved on their work by incorporating a Miura fold, an origami technique. The Miura fold is in use today to transport solar panels in satellites so they can be easily unpacked into big sheets once they arrive in outer space. The team printed all four droplets on a sheet, laser-cut in a Miura fold pattern, that could then be folded to stack the droplets to generate electricity.
University of Michigan professor of materials science and engineering Max Shtein said in a statement, “The eel polarizes and depolarizes thousands of cells instantaneously to put out these high voltages. It’s a fascinating system to look at from an engineering perspective – its performance metrics, its fundamental building blocks and how to use them.”
The technology is still preliminary, but the team is working on boosting the power source’s efficiency. The journal Nature published the research online in December.