Mouldy bread might be pretty low on your list of favourite things, but a fungus growing on last week’s loaf could be the key to a better recharge.
Researchers have found that a type of bread mould can be used to produce more sustainable lithium-ion batteries. The findings are published today in Current Biology.
Lithium-ion batteries are popular in consumer electronics, such as your laptop or smartphone. They’re efficient and rechargeable, but don’t live very long; hence researchers have been looking for ways to improve li-ion energy density, cycle durability, and charge time.
Amongst attempts to improve the common battery are experiments using different electrodes and other sources of manganese oxides – but this study is the first to use fungi.
Lead author Professor Geoffrey Gadd from the University of Dundee in Scotland, says using a fungus to produce the metal oxides needed for more efficient lithium-ion batteries “appears to be very simple”.
“These bio-materials could provide alternatives to those currently used in electrochemical devices,” he suggests.
Mould shows potential
The researchers found that the fungus Neurospora crassa, a common red bread mould, can produce electrochemically-active materials from manganese through a common biological process called biomineralisation – essentially the same process the human body uses to create bones.
Through fungal biomineralisation, the researchers acquired a material that was part biomass, part manganese oxides. As battery fuel, this mould-produced material performed surprisingly well. Compared with other lithium-ion batteries containing manganese oxide, they “showed an excellent cycling stability, and 90% capacity was retained after 200 cycles,” says Gadd.
“This is the first demonstration of the synthesis of active electrode materials using a fungal biomineralisation process,” Gadd explains.
“It illustrates the great potential of fungal biomineralisation as a source of useful biomaterials.”
The team has previously studied other attributes of mould – in earlier studies, the researchers demonstrated that fungi were able to stabilise toxic lead and uranium. This led them to look for other helpful uses for fungi.
Professor Thomas Nann, Director of the MacDiarmid Institute for Advanced Materials and Nanotechnology, says the study “is not only an example of rigorous and in-depth research, but also shows inspiring out-of-the-box thinking.”
“Many paradigm-shifting discoveries started as ‘crazy’ ideas, and we clearly need more of them!” he adds.
Professor Gadd is continuing to look at ways to improve the mouldy battery, and is also interested in other organisms that could produce or recover metal elements.
“Fungi, as well as other microorganisms, play highly significant roles in metal and mineral biotransformations in the environment,” he says.
If we can harness these transformations to power our digital tech, a piece of mouldy bread will be nothing to sniff at.