Wood battery
A closeup of the soft battery, created with wood pulp nanocellulose Max Hamedi and Wallenberg Wood Science Center

Researchers from Sweden and US have unveiled a method of making high-capacity batteries from wood pulp.

A team from KTH Royal Institute of Technology and Stanford University, used nanocellulose broken down from tree fibre to produce an elastic, foam-like battery material that is designed to withstand shock and stress.

"It is possible to make incredible materials from trees and cellulose," says Max Hamedi, a researcher at KTH and Harvard University.

The benefit of the new wood-based aerogel material is that it can be used for three-dimensional structures.

"There are limits to how thin a battery can be, but that becomes less relevant in 3D. We are no longer restricted to two dimensions. We can build in three dimensions, enabling us to fit more electronics in a smaller space," he said.

The researcher further believes the 3D structure is capable of significantly more power storage in a less amount of space, when compared to conventional batteries.

"Three-dimensional, porous materials have been regarded as an obstacle to building electrodes. But we have proven that this is not a problem. In fact, this type of structure and material architecture allows flexibility and freedom in the design of batteries," adds Hamedi.

These aerogel batteries could be used in electric car bodies and clothing, provided the garment has a lining.

The method used to create wood battery

The elastic, foam-like battery material is created by breaking down tree fibre, while making them approximately one million times thinner. The nanocellulose from tree fibre is then dissolved, frozen, and then freeze-dried so that moisture evaporates without having to pass through a liquid state.

The material also goes through a process in which molecules are stabilised so that the material does not collapse.

"The result is a material that is both strong, light and soft. 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 finished aerogel can then be treated with electronic properties. 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," explains Hamedi.

While flexible and stretchable electronics already exist, the concept of insensitivity to shock and impact are new, affirms Hamedi.

More details about the elastic high-capacity battery from wood are available at AlphaGalileo.