An alkaline anion exchange membrane (AAEM) is a semipermeable membrane generally made from ionomers and designed to conduct anions while being impermeable to gases such as oxygen or hydrogen. This is their essential function when incorporated into a membrane electrode assembly (MEA) of a direct methanol fuel cell (DMFC) or direct-ethanol fuel cell (DEFC): separation of reactants and transport of anions.
Advantages
The advantage of the alkali anion exchange membrane in the fuel cell is the potential to use non-noble metals such as iron, cobalt or nickel due to the low overpotentials associated with electrochemical reactions at high pH. In comparison, against alkaline fuel cell, alkali anion exchange membrane fuel cells also protect the electrode from solid carbonate precipitation, which can cause fuel (oxygen/hydrogen) transport problem during start-up.