
Biobatteries are an emerging technology that utilizes biological organisms to generate electricity, representing a promising alternative to conventional power sources. These eco-friendly devices harness natural processes to create energy, with fungi being a particularly compelling candidate for finding sustainable energy solutions. Researchers are increasingly investigating the potential of fungi to power small devices, offering a biodegradable battery option as an alternative to traditional, non-biodegradable batteries.
The fungal microbial fuel cell innovation
A recent breakthrough from the Swiss Federal Laboratories for Materials Science and Technology (EMPA) has resulted in the development of a fungal microbial fuel cell. Although not yet powerful for large-scale use, this bio-based battery can generate sufficient electricity to power small devices, such as temperature sensors used in agriculture and environmental monitoring. Unlike conventional batteries, the fungal battery is both non-toxic and biodegradable, making it an environmentally safe alternative.

The grid printed electrode contains the fungus used in the anode compartment of the battery. Courtesy of EMPA.
Battery vs. fuel cell: What's the difference?
While both batteries and fuel cells are used to generate electricity, they operate differently. A battery stores energy chemically in a closed system and releases it as electrical power when needed. Once the energy is depleted, the battery must be recharged or replaced. On the other hand, a fuel cell generates electricity continuously if it receives a supply of fuel (such as hydrogen or, in this case, nutrients for the fungi). Unlike a battery, a fuel cell does not store energy; it produces power through a chemical reaction between the fuel and oxygen. In the case of the fungal microbial fuel cell, living fungi convert nutrients into energy, capturing some of that energy as electricity.
How the fungal battery works
The EMPA team combined two types of fungi to create this unique microbial fuel cell. A yeast fungus on the anode side releases electrons, while a white rot fungus on the cathode captures and conducts these electrons, completing the energy circuit.
The fungi are not merely added to the battery; they are integral to its design, with electrodes 3D-printed to optimize their growth and energy production. "You can store the fungal batteries in a dried state and activate them on location by simply adding water and nutrients," stated Carolina Reyes, one of the lead researchers. The researchers also included cellulose-based materials in the battery, which serve as a nutrient source for the fungi and ensure biodegradability after the battery’s use.
Challenges and future potential
The researchers faced challenges finding materials that supported fungal growth and were electrically conductive. However, their success in creating a suitable 3D-printing ink based on cellulose has paved the way for future improvements. According to the announcement, the team aims to increase the battery's power and longevity while exploring additional fungal species for better efficiency. As fungi are still under-researched in materials science, this innovation could open the door to more sustainable, biologically based energy solutions in the future.
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