For decades, paper mills have long used a thick sticky byproduct of the wood-pulping process—”Brown Liqour”— as a combustible fuel to keep the mills in motion. Now a collaborative research project by scientists at Linköping University in Sweden and Poznan University of Technology in Poland has found a way to transform this “brown liqour” into a battery cathode which could cut out the need for expensive rare metals used in batteries such as cobalt. While we may not be huge fans of cutting down trees, the brown liquor tech could reduce the cost of batteries and has the potential to increase our ability to store and distribute solar and wind power.
Olle Inganas and Grzegorz Milczarek drew inspiration for the organic cathode from the process of photosynthesis. Noting that electrons charged by solar energy are transported by quinones in the process, they found that the lignins in the brown liquor contain organic compounds which can be converted into energy-transmitting quinones. The gooey fuel works in a battery application when “lignin derivatives from the brown liquor and combined them with a conductive polymer called “polypyrrole.” Together, the materials make for a cathode that’s both conductive and can hold a charge,” according to Discovery News.
Olle Inganas, who previously spent many years researching solar cell technology, hopes that the lignin batteries could provide renewable energy storage as we begin to develop more efficient solar cells and wind turbines. The technology has not been perfected — at present the batteries with a lignin cathode will not hold a charge while idle. But if brown liqour battery cathodes can be perfected they could open the door to cheaper batteries made from a source less finite than the rare metals presently utilized.