Wood Energy - VideoTuesday 30th July 2013
We are all used to batteries, whether disposable or rechargeable ones - most would recognize a battery of whatever type when seeing one - but how about a battery made of wood?
Scientists at the University of Maryland have been working on exactly that - making a sliver of wood, coated with tin, into a tiny, long-lasting, efficient and environmentally friendly battery.
No - don’t grab your whittling knife with a view to powering your iPhone or flashlight, it takes a little more ingenuity than that as the components in the battery tested at the University of Maryland are a thousand times thinner than a piece of paper!
They also used sodium instead of the oft utilized lithium, which is in many rechargeable batteries, making the ‘wooden’ battery environmentally benign, but sodium doesn’t store energy as efficiently as lithium, so you won’t see this battery in your cell phone.
The ‘wooden’ version though is low cost and uses common materials making it ideal to store a huge amount of energy from sources such as solar energy or even from a power station.
Liangbing Hu, Teng Li and their team found that wood fibers are supple allowing their sodium-ion battery to last more than 400 charging cycles, which puts it among the longest lasting nanobatteries.
Existing batteries are often created on stiff bases, which prove to be too brittle to withstand the swelling and shrinking that happens as electrons are stored in and then used up from the battery.
"The inspiration behind the idea comes from the trees," said Hu, an assistant professor of materials science. "Wood fibers that make up a tree once held mineral-rich water, and so are ideal for storing liquid electrolytes, making them not only the base but an active part of the battery."
Lead author Hongli Zhu and other team members noticed that after charging and discharging the battery hundreds of times, the wood ended up wrinkled but intact. Computer models showed that that the wrinkles effectively relax the stress in the battery during charging and recharging, so that the battery can survive many cycles.
"Pushing sodium ions through tin anodes often weaken the tin’s connection to its base material,” said Li, an associate professor of mechanical engineering. "But the wood fibers are soft enough to serve as a mechanical buffer, and thus can accommodate tin’s changes. This is the key to our long-lasting sodium-ion batteries."
Interesting research, a different slant on Bio-fuels!
Watch the video:
Tuesday 30th July 2013