Metal–air electrochemical cell

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The types of metal–air batteries have different capacities

A metal–air electrochemical cell is an electrochemical cell that uses an anode made from pure metal and an external cathode of ambient air, typically with an aqueous electrolyte.[1][2]

Types[edit]

The Li–air battery discharge reaction between Li and oxygen Li2O, according to 4Li + O2 → 2Li2O, has an open-circuit voltage of 2.91 V and a theoretical specific energy of 5210 Wh/kg. Since oxygen is not stored in the battery, the theoretical specific energy excluding oxygen is 11,140 Wh/kg (40.1 MJ/kg). Compare this to the figure of 12,200 Wh/kg (44 MJ/kg) for gasoline (see petrol energy content).

Metal–air battery Theoretical specific energy, Wh/kg
(including oxygen)
Theoretical specific energy, Wh/kg
(excluding oxygen)
Calculated open-circuit voltage, V
Aluminium–air 4300[3] 8140[4] 1.2
Germanium–air 1480 7850 1
Calcium-air 2990 4180 3.12
Iron–air 1870 14730 1.3
Lithium–air 5210 11140 2.91
Magnesium–air 2789 6462 2.93
Potassium-air 935[5][6] 1700[Note 1] 2.48[5][6]
Sodium–air 1677 2260 2.3[7][8]
Silicon–air 6110 14230 1.6
Tin–air at 1000K 860 6250 0.95
Zinc-air 1090 1350 1.65

See also[edit]

References[edit]

Notes[edit]

  1. ^ Calculated from the specific energy density (including oxygen) value and 39.1 and 16 atomic weight data for K and O respectively for KO2