Metal air batteries have been attracting many works in the
electrochemistry research and development communities for the
last 50 years. They have much higher specific energies than most
currently available primary and rechargeable batteries. Their
attractiveness lies in their source of oxidizing agent: for the
cathodic reaction the oxygen comes from outside environment,
mostly from air or O2, rather than from inside the battery. These
aspects lead to high densities of specific energy (Wh kg1), in
theory much higher than those of Li-ion batteries