Eco-Friendly Batteries Made Using Wood Slivers

Researchers at the University of Maryland have created a battery that is made of a sliver of wood, coated with tin. This eco-friendly battery is a 1000 times thinner than paper and can last longer than a commercial battery.

The battery has sodium instead of lithium which makes it eco friendly. However, the battery can't store energy as efficiently as lithium which is why researchers say that the new batteries are ideal for storing large amount of energy at once. They can be used at a power plant or to store solar energy.

Recently, a team of researchers from Harvard University and their colleagues showed that, miniature batteries could be built using 3D printing technology.

Most rechargeable batteries designed today are built on surfaces that are too brittle to withstand the changing shape of a battery- a battery swells or shrinks depending on the movement of electrons. Researchers found that wood sliver is supple enough to support the changes in the battery. Their study found that these new wood-based batteries can last for over 400 charging cycles, making them one of those few long-lasting batteries.

"The inspiration behind the idea comes from the trees. 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," said Liangbing Hu, an assistant professor of materials science and an author of the study.

Researchers found that recharging the new battery several times led to the wood getting wrinkled but remained intact otherwise. Analysis of the cracks showed that these wrinkles cushioned the stress in the battery, which helped it last longer.

"Pushing sodium ions through tin anodes often weaken the tin's connection to its base material. 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," Hongli Zhu, lead author of the study said in a news release.

The complete study is published here.