Tree Batteries?
A method has been discovered for making elastic high capacity batteries from the wood pulp found in trees. Using the Nano-cellulose broken down from tree fibers the research group was able to produce an elastic foam-like battery that can withstand physical shocks and mechanical stresses applied to it.
“It is possible to make incredible materials from trees and cellulose,” says Max Hamedi, who is a researcher at KTH and Harvard University.
He goes onto say that “one of the primary benefits of the new wood-based aerogel material is that it can be introduced into three dimensional structures. There are limits to how thin a battery can be, but that becomes less relevant in 3D,” Hamedi says. “We are no longer restricted to two dimensions. We can build in three dimensions, enabling us to fit more electronics in a smaller space.”
Having the optional use of a 3 dimensional structure for a battery can store significantly more power than conventional batteries. As 3D porous materials have been regarded as an obstacle in the construction of electrodes but with this find this is no longer a problem. This type of structure and material architecture can allow the flexibility to design augmented batteries for specific machines and devices.
To create this material the researches must first breakdown tree fibers making them 1 million times thinner, next the nano-cellulose is dissolved, frozen and then freeze dried so that all moisture is lost within the material. Finally the material left is pushed through a process in which the molecules are stabilized so that the material doesn’t collapse.
“The result is a material that is both strong, light and soft,” Hamedi says. “The material resembles foam in a mattress, though it is a little harder, lighter and more porous. You can touch it without it breaking.”
The now produced aerogel is treated to produce the desired electrical properties, Hamedi says “We use a very precise technique, verging on the atomic level, which adds ink that conducts electricity within the aerogel. You can coat the entire surface within.”
The surface area which is now covered within the aerogel is that of a football field as a single cubic decimeter of the battery material would cover most of this. The aerogel can be pressed as much as the user wants, and while flexible electronics does exist it is the first time an electrical device can sustain a physical shock.
Hamedi says the aerogel batteries could be used in electric car bodies, as well as in clothing, providing power to many types of applications.
Journal Reference:
- Gustav Nyström, Andrew Marais, Erdem Karabulut, Lars Wågberg, Yi Cui & Mahiar M. Hamedi. Self-Assembled Three-Dimensional And Compressible Interdigitated Thin Film Supercapacitors And Batteries. Nature Communications, May 29, 2015 DOI:10.1038/ncomms8259
Below is a picture of the battery created:
Courtesy of Max Hamedi and Wallenberg Wood Science Center
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