Magic Mushrooms: Fungi May Help Make Better Batteries, Researchers Say

It still won’t be grow-your-own, but researchers have devised a way to produce batteries using mushrooms.

Purdue University says carbon fibers derived from a sustainable source – a type of wild mushroom modified with nanoparticles – outperform conventional graphite electrodes for lithium-ion batteries.

Associate Professor Vilas Pol says the electrodes are created from the species Tyromyces fissilis.

“Current state-of-the-art lithium-ion batteries must be improved in both energy density and power output to meet the future energy storage demand in electric vehicles and grid energy-storage technologies,” Pol says. “So there is a dire need to develop new anode materials with superior performance.”

Batteries have two electrodes, called an anode and a cathode, and the anodes in most Li-ion batteries are made of graphite.

Lithium ions are contained in a liquid called an electrolyte, and these ions are stored in the anode during recharging.

Doctoral student Jialiang Tang got the idea of tapping fungi for raw materials while researching alternative sources for carbon fibers.

“The methods now used to produce carbon fibers for batteries are often chemical-heavy and expensive,” Tang says

He noticed a mushroom growing on a rotting wood stump in his backyard and decided to study its potential as a source for carbon fibers.

“I was curious about the structure, so I cut it open and found that it has very interesting properties,” Tang says. “It’s very rubbery and yet very tough at the same time. Most interestingly, when I cut it open it has a very fibrous network structure.”

Comparisons with other fungi showed the Tyromyces fissilis is especially abundant in fibers. Those 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.

They have a disordered arrangement and intertwine like spaghetti noodles.

Pol says they form a conductive interconnected network that brings faster electron transport, which could result in faster battery charging.

The carbon fibers derived from Tyromyces fissilis and modified by attaching cobalt oxide nanoparticles outperform conventional graphite in the anodes, the researchers say.

The hybrid design has a synergistic result.

“Both the carbon fibers and cobalt oxide particles are electrochemically active, so your capacity number goes higher because they both participate,” Pol says.

The hybrid anodes have a stable capacity of 530 milliamp hours per gram, which is one and a half times greater than graphite’s capacity.