IMPROVING BATTERY PERFORMANCE BY FUNGUS
Carbon fibers derived from a sustainable source, a type of wild mushroom, and modified with nanoparticles have been shown to outperform conventional graphite electrodes for lithium-ion batteries. Researchers at Purdue University have created electrodes from a species of wild fungus called Tyromyces fissilis.
The anodes in most of today's lithium-ion batteries are made of graphite. Lithium ions are contained in an electrolyte, and those ions are stored in the anode during recharging.
The researchers have found that carbon fibers derived from Tyromyces fissilis and modified by attaching cobalt oxide nanoparticles outperform conventional graphite in the anodes. The hybrid design has a synergistic result.
The hybrid anodes have a stable capacity of 530 mAh/g, which is one and a half times greater than graphite's capacity.
One approach for improving battery performance is to modify carbon fibers by attaching certain metals, alloys or metal oxides that allow for increased storage of lithium during recharging. The researchers got the idea of tapping fungi for raw materials while researching alternative sources for carbon fibers.
Comparisons with other fungi showed the Tyromyces fissilis was especially abundant in fibers. The fibers are processed under high temperatures in a chamber containing argon gas using a procedure called pyrolysis, yielding pure carbon in the original shape of the fungus fibers. The fibers have a disordered arrangement and intertwine like spaghetti noodles. The interconnected network brings faster electron transport, which could result in faster battery charging.