Magnesium-air batteries

Additionally, there are several magnesium batteries that are experimental, or in various stages of development iii) Magnesium-air batteries are also aqueous, primary batteries, but these use oxygen from the air for reduction at the cathode. Although much effort has been devoted for their development, up to date they have not been commercialized, iv) Magnesium-organic solvent... 

A further point is that the method does not stand very good comparison with metal air batteries. If the user is prepared to use quantities of water, and is prepared to dispose of water/metal hydroxide mixtures, then systems such as the aluminium/air or magnesium/air battery are preferable. With a salt-water electrolyte, an alumininm/air battery can operate at 0.8 V at quite a high current density, producing three electrons for each aluminium atom. The electrode system is much cheaper and simpler than a fuel cell. 

Magnesium/air batteries were studied, again because of the higher operating voltage than with zinc (see Chap. 38). These batteries, too, were never commercialized. Magnesium, however, is a very useful anode in reserve batteries. Its application in these types of batteries is covered in Chap. 17. 

The discharge reaction mechanisms of the magnesium/air battery are Anode Mg — Mg" + 2e... 

Magnesium/air batteries have not been sueeessfully commercialized and an effort has been directed to undersea applications using the dissolved oxygen in seawater as the reactant. The battery uses a magnesium alloy anode and a catalytic membrane cathode, and is activated by the seawater. The main advantage of this system is that, with the exception of the magnesium, all of the reactants are supplied by the seawater. The battery can have a specific energy of about 700 Wh/kg. 

Magnesium-air batteries have a magnesium metal anode paired with an air cathode. The electrolyte system is aqueous and usually alkaline. Sometimes seawater is used as the electrolyte. The discharge reaction mechanisms of the magnesium-air battery are ... 

Magnesium is one of the most abundant metals in the earth. The discharge reaction in the magnesium-air battery can be expressed as [75]... 

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