The air metal battery uses oxygen in the ambient air. The aluminum air battery has a very high energy density, up to 300 Wh per one lb of aluminum. The power density is also very high, about 30 Watt / lb. This type of battery cannot be charged by electricity. Basically this is a primary battery. However, the difficulty of recharging can be overcome by mechanical recharging. Adjusting the mechanical function of the aluminum air cell is done with all of the aluminum electrode.
Generally, for non-aqueous metal-O2, when the battery is discharged, the metal ions in the metallic anode are transported through the electrolyte into the air cathode pores. The O2 of the atmosphere enters the cathode and dissolves into the electrolyte in the pores. The porous carbon is then reduced by external electrons on the electrode surface and leads to the formation of a solid metal oxide (MxOy) for the secondary and factory product by the metal ion (Mn +) from the electrolyte. Remarkably, the reaction is reversible in varying degrees.
One of the major disadvantages of the metal-air battery is the evaporation of the liquid electrolyte. Therefore, glycerin may be added to the NaCl electrolyte to prevent evaporation of the liquid electrolyte.
Modern society requires energy storage devices with a much higher level of energy storage than before. Rechargeable metal-O2 cells are among a number of competitors that can exceed the stored energy of the state-of-the-art Li-ion cells. The multivalent metal-air (O2) battery described here has an important potential for high-energy storage applications, but is a long way as a technological product in most general examples (except for the primary zinc-air commercialized for several years). All aspects of the cell, anode, electrolyte and cathode need to be addressed.
Theoretical Energy Storage
The theoretical specific energies (gravimetric energy densities) and energy intensities (volumetric energy densities) for a series of metal-O2 batteries are given in Table I.