Metaleair batteries are roughly comprised of four parts:
metal anode, electrolyte, separator and air cathode (Fig. 1).
The separator is an insulator which can only allow the transformation
of ions. In the discharge process, oxidation reactions
occur to the metal anode with metal dissolved in the electrolyte
and oxygen reduction reaction (ORR) is induced in the air
cathode. Due to the open battery configuration that uses air as
the reactant, metaleair batteries own much higher specific
capacity. Although they have high energy density, there are
tremendous challenges in these systems that must be overcome
before they are put into practical uses.