How toxic algal blooms could boost your phone battery
Tuesday, October 13, 2015, 10:35 AM - The quest for a better battery is ongoing, but scientists at Wayne State University in Detroit found a potential solution in one of the weirdest places: A harmful algae bloom on Lake Erie.
"Unlike terrestrial plants, they need no land or soil. If [harmful algae blooms] could be harvested on a large scale, it could not only possible to mitigate the issue .... but also provide a source of biomass," the researchers write in the latest issue of Environmental Science & Technology.
Such blooms, which can occur in the Great Lakes, look pretty from the air, but they're a nightmare for lake dwellers both in and around the waters.
The blooms, composed of countless microorganisms known as cyanobacteria, produce toxins that can be harmful to humans. A massive bloom in 2014 prompted authorities in Toledo, Ohio, to warn around half a million people not to drink the tap water, and similar blooms elsewhere have occasionally killed sea life. The Lake Erie bloom resurfaced again this summer.
They thrive on minerals found in agricultural runoff, as well as warmer lake waters due to increasing global temperatures.
That's where the research comes in. Taking a literal "trash for treasure" approach, the scientists propose harvesting the algae for use as low-cost electrodes in sodium ion batteries, which the International Business Times says are typically cheaper than lithium ion power sources.
They made it into a usable material by harvesting it from the lake and baking it at 1,000oC in argon gas overnight, and found that it was in fact usable as an electrode.
There's some downsides to the technology, which is still just in its infancy. Although the electrodes initially had a capacity of 440 milliamp hours per gram, that dropped down to 230 mAh/g after the first use, according to IBT (although they stayed at that capacity for subsequent uses). Sodium ion batteries in general also take longer to charge.
But the upside is that unlike lithium, which is being depleted, sodium is abundant, and less toxic.
As encouraging as the latest research is, though, it'll be awhile before more research can turn algae into industrial scale battery components.
With files from Scott Sutherland