Skip the Recycling Bin With This Battery That Dissolves in Water
A self-destructing cell phone sounds like something out of a spy movie, but it might soon be a reality thanks to researchers at Iowa State University. Scientists at the school have developed a transient battery that can power electronic devices for a short amount of time and then dissolves after being immersed in water for 30 minutes.
The tiny frame and low power-supply duration—it can power a laptop for about 15 minutes—makes the lithium-ion battery ideal for both keeping secrets away from prying eyes and for powering medical implant devices, which the researchers have suggested as possible uses.
“Unlike conventional electronics that are designed to last for extensive periods of time, a key and unique attribute of transient electronics is to operate over a typically short and well-defined period, and undergo fast and, ideally, complete self-deconstruction and vanish when transiency is triggered,” the researchers wrote in a paper published in the June 2016 edition of the Journal of Polymer Science Part B: Polymer Physics.
The dissolving battery could also help reduce the amount of e-waste generated when people don’t recycle the batteries they use to operate consumer electronics. Of the 3 billion batteries purchased for cell phones and other popular consumer products every year, only 20 to 40 percent are recycled. The rest make their way into landfills and oceans, leaving environmental activists concerned about the effect that throwing away batteries has on soil and water supplies.
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The new battery is a complex example of prototype transient electronics, which disintegrate when exposed to heat or liquid. Researchers have experimented with edible water-activated batteries before, but this latest product is the first fit for practical use.
“This is a battery with all the working components. It’s much more complex than our previous work with transient electronics,” lead researcher Reza Montazami said in a statement.
The scientists encased lithium-ion technology in biodegradable polymer to give it its powerful charge. The 2.5-volt battery is nearly twice as powerful as an alkaline AAA battery.
The battery’s dimensions (it’s one millimeter thick, five millimeters long, and six millimeters wide) make it smaller than a stick of chewing gum. A bigger battery is capable of storing more power, but researchers found that anything larger takes longer to dissolve.
Further development of the battery is needed before it’s available for use in devices. Montazami said in the statement that the battery doesn’t always fully dissipate after spending half an hour in liquid. When the polymer case bloats and breaks apart the electrodes, the microparticles that remain “don’t degrade, but they do disperse.” The researchers have not said whether the insoluble microparticles in the battery are dangerous to animals and humans.