According to the American Association for the Advancement of Science (AAAS), scientists have discovered that a plentiful natural byproduct of the pulp and paper industry – lignin – can be used to store an electrical charge. They have even used the material in creating a prototype lignin-based rechargeable battery, adding that one day this material can be used as a low-cost and safe alternative to the precious metals that currently being used in the manufacture of battery cathodes.
Lignin, found in plants, is said to be the second-most common polymer naturally produced by a living organism, following cellulose. When wood fiber is processed in paper mills, the lignin content is removed, leaving cellulose required for paper production. Importantly, organic compounds known as quinones that occur in lignin form the foundation for the experimental battery.
Grzegorz Milczarek, from Poland’s Poznan University of Technology, along with Olle Inganäs from Sweden’s Linköping University, have blended a lignin derivative with a conductive polymer, polypyrrole.
“The advantage of using a renewable material for charge storage is the enormous amount of this material that is already being produced on Earth by growing plants, which contain about 20 to 30 percent lignin,” Inganäs said. “It is also a low-value material, currently being used for combustion. Lithium-ion batteries, on the other hand, require metal oxides and some of those materials, such as cobalt, are rather rare.”
Although the battery does lose its charge when sitting idle, Milczarek and Inganäs found that different types of lignin derivatives offered different levels of performance, and believe that they could find one that allows for better charge storage.
Photo: Tetra Pak