Squishy battery created using wood
Wood pulp-derived nanocellulose is turning out to be pretty useful stuff. Previously, we'd heard how it could be used in things like high-strength lightweight composites, oil-absorbing sponges and biodegradable computer chips. Now, researchers from Sweden and the US have used the material to build soft-bodied batteries that are more shock- and stress-resistant than their traditional hard counterparts.
Nanocellulose is also known as nanofibrillated cellulose or Cellulose NanoFibrils (CNF). In a nutshell, it's typically made using wood waste from sources such as lumber or paper mills, which has been added to water and then mechanically ripped apart to the point that the wood fibers are rendered into much smaller cellulose nanofibers. The resulting gel is subsequently freeze-dried, thus removing the water and leaving behind the long and interconnected nanofibers.
In the case of the latest research, scientists from Sweden's Royal Institute of Technology (KTH) and California's Stanford University used CNF to create a lightweight porous aerogel-like material. "The material resembles foam in a mattress, though it is a little harder, lighter and more porous," says KTH researcher Max Hamedi. "You can touch it without it breaking."
The material was then treated inside and out with an electrically-conductive ink, allowing it to hold an electrical charge. Because it's three-dimensional, it's reportedly able to store more power in less space than a conventional battery, which uses coiled two-dimensional materials. In fact, it's claimed that if spread out flat, a cubic decimeter of the CNF material could cover most of a football field.
It is now hoped that once developed further, the batteries could be used in applications such as flexible electronics, smart fabrics and safer electric cars.
This isn't the first time, incidentally, that scientists have built a "wooden battery." We previously heard about researchers at the University of Maryland using wood fibers in longer-lasting sodium-ion batteries.