A team of researchers from Northwestern University has demonstrated a remarkable new way of generating electricity in which a device the size of a paperback book is placed in soil and receives the energy created when microbes decompose dirt as long as carbon is present in the soil.
So-called microbial fuel cells have been around for more than a century, and their working principle is similar to batteries with an anode, cathode and electrolyte. However, instead of getting electricity from chemical sources, they use bacteria that share electrons as they absorb soil.
The problem was maintaining water and oxygen levels in them when buried underground, so a team of US scientists came up with several designs to ensure the cells had access to oxygen. A cartridge-shaped version on top of a horizontal disc was found to be the best. The disc-shaped carbon anode sits at the bottom of the device, being buried deep in the ground, while a conductive metal cathode sits on top of the anode.
