luftkathode

A luftkathode (German for "air cathode") is a type of electrode used in electrochemical systems, particularly in microbial fuel cells (MFCs) and some types of fuel cells or sensors. Unlike traditional metal-based cathodes, a luftkathode relies on atmospheric oxygen as its primary reactant, eliminating the need for external oxygen supply systems.

In microbial fuel cells, the luftkathode serves as the site where oxygen from the air reduces electrons produced by microbial metabolism. This process facilitates the transfer of electrons from anode to cathode, generating electricity. The cathode is typically constructed from conductive materials such as carbon paper, carbon cloth, or graphite, often coated with a catalyst like platinum or a non-precious metal catalyst to enhance efficiency. In some cases, the cathode may incorporate a hydrophobic layer to prevent water intrusion while allowing oxygen diffusion.

Luftkathodes are favored in portable and low-power applications due to their simplicity and cost-effectiveness. They reduce system complexity by eliminating the need for oxygen pumps or pressurized gas supplies. However, their performance can be influenced by environmental factors such as humidity, temperature, and air circulation, which may affect oxygen availability and mass transfer efficiency.

Beyond MFCs, luftkathodes are also explored in biosensors and environmental monitoring devices where oxygen reduction is a key reaction. Their design continues to evolve, with research focusing on improving durability, catalytic activity, and overall energy conversion efficiency.