Researchers at the University of Maryland are using tin-coated wood for anodes in a sodium ion battery. The battery is cheap to make and environmentally friendly unlike lithium ion.
Why a wooden base for the anodes? Because wood has the ability to morph in response to electrons without becoming brittle. This suppleness means the battery can withstand up to 400 charging cycles.
The components in the battery are tiny and very thin, in fact thinner than a piece of a paper. The choice of sodium as the medium for holding the charge is about cost and environmental impact. Sodium is readily available although it doesn’t hold a charge as well as lithium. And wood is a great material for storing a liquid electrolyte. After all trees do this naturally in drawing fluid and nourishment from root systems into the trunk and leaves.
To construct the battery microscopic wood fibers from Yellow Pine like the ones seen in the image below are coated with a nano layer of tin. When charged the natural wrinkling within the fibers demonstrates a flexibility that is not possible with a stiffer medium. The result, a battery that easily handles repeated cycles of charging and discharge.
Where would such a battery be considered useful? For large scale energy storage state the researchers who see their wood coated with tin invention as an ideal solution to support variable renewable energy such as solar and wind power plants.