Soil-based Microbial Fuel Cells

• Context (IE): A team led by Northwestern University developed a new fuel cell that can harvest energy from microbes living in the soil.
• Instead of using chemicals to generate electricity, they harvest electricity from bacteria that naturally give out electrons to nearby conductors.
• These electrons flow from anode to cathode to create an electric circuit.
• It can last forever as long as there is organic carbon in the soil for the microbes to break down.
• It can potentially be used in green infrastructure and precision agriculture applications.

Fuel Cells

• A fuel cell is a device that converts chemical energy into electrical energy.
• It uses hydrogen and oxygen gas as fuel to generate electricity. However, there is no combustion involved.
• Fuel cells can vary from tiny devices producing only a few watts of electricity, right up to large power plants producing megawatts.

Fuel Cell Mechanism

• A fuel cell consists of a cathode, an anode, and an electrolyte.
• The electrolyte enables the movement of the ions between the electrodes.
• At the anode, catalyst causes the fuel to undergo oxidation & generates +ve charged ions & electrons.
• The ions move from the anode to the cathode and the same time, the electrons flow from the anode to the cathode through an external circuit, producing direct current electricity.
• At the cathode, another catalyst causes ions, electrons, & oxygen to react, forming water as by-product.
• The reaction rate of this electrochemical reaction is quite low.
• Catalysts such as platinum or palladium or gold are used to speed up the reaction.