The first thing that many people think of when they hear the word "fungi" is the kind that turns bread moldy and inedible. Now, a new study reveals that red bread mold (Neurospora crassa) might be the key to creating sustainable electrochemical materials for the production of rechargeable batteries due to its ability to transform manganese into a mineral composite with beneficial electrochemical properties.
"We have made electrochemically active materials using a fungal manganese biomineralization process," said Geoffrey Gad, who led the study. "The electrochemical properties of the carbonized fungal biomass-mineral composite were tested in a supercapacitor and a lithium-ion battery, and it [the composite] was found to have excellent electrochemical properties. This system therefore suggests a novel biotechnological method for the preparation of sustainable electrochemical materials."
Gadd and his team have years of experience researching the ability of fungi to transform metals and minerals for unique purposes, and the current study was conducted after they wondered whether fungi could be used in the creation of novel electrochemical materials.
"We had the idea that the decomposition of such biomineralized carbonates into oxides might provide a novel source of metal oxides that have significant electrochemical properties," Gadd said.
Although previous research has attempted to improve battery performance using alternative electrode materials, few of these studies focused on examining the potential of fungus to benefit the manufacturing process.
Gadd and his team incubated the N. crassa fungi in media combined with urea and manganese chloride and observed the results. They found that the long filaments of the fungi were biomineralized and/or consumed by minerals and after heat treatment, a mixture of carbonized biomass and manganese oxides remained.
After examining these remaining structures, the team discovered that their electrochemical properties were ideal for use in supercapacitors or lithium-ion batteries.
"We were surprised that the prepared biomass-Mn oxide composite performed so well," Gadd said, adding that it "showed an excellent cycling stability and more than 90 percent capacity was retained after 200 cycles" in comparison to other reported manganese oxides and lithium-ion batteries.
Gadd and his team are the first to show that active electrode materials can be created using a fungal biomineralization process and will continue to explore the potential of fungi in the production of useful metal carbonates.
The findings were published in the March 17 issue of Current Biology.
