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6 Nanomaterials for Batteries
6.4.4 Advantages and Disadvantages of Metal-Air Batteries
(1) High specific energy. Since the cathode electrode active material comes from
the outside of the battery, it does not need to occupy the space of the battery.
In the same volume and weight, the metal-air battery can be loaded with more
anode electrode active materials, so that the metal-air battery has a much higher
capacity than the ordinary battery. The specific energy of zinc-air battery theory
is over 1350 Wh/kg, and the actual specific energy is over 1000 Wh/kg. It
belongs to high capacity and high-energy chemical power supply.
(2) Low prices. The resources of some metal (such as zinc, aluminum, and magnesium) are abundant and cheap. Oxygen is derived from the ambient air and is
basically the same as the commonly used lead-acid battery.
(3) Stable performance and stable discharge. Since the cathode catalyst itself does
not change during discharging, and the voltage of zinc electrode is stable, the
change of the voltage is small during discharge.
(4) Excellent storage life. The metal-air battery currently produced is actually a
reserve type battery. Because the sealing process is used in the storage process,
the air hole of the battery is isolated from the outside air. Therefore, the battery
capacity loss is minimal, less than 2% per year.
(5) Safe and reliable, no pollution. The whole process from production to use will
not pollute the environment; it will not pollute the environment, nor will it burn
and explode. It can be called green energy.
Although the zinc-air battery has many advantages mentioned above, there are
still some deficiencies and restricts its large-scale commercial application. The first
problem is self-corrosion of the zinc electrode. Since zinc is thermodynamically
unstable in alkaline solutions, zinc will be accompanied by a small amount of
hydrogen evolution corrosion reaction while discharging in the alkaline electrohydraulic solution. The second problem is carbonation of the air electrode. Since the
battery is discharged for a long time, the reaction product or alkaline electrolyte will
produce a large amount of carbonate when it comes in contact with the outside CO 2 .
When the carbonate is dissolved and saturated, it will precipitate on the upper surface
of the air electrode. This causes the air electrode to become clogged and degrades
in performance and energy, and will no longer work by replacing the zinc negative
electrode with energy. Third, because the air battery is a semi-open system, excessively high or low humidity environment will trigger the phenomenon of “drowning”
or “drying up” of the air electrode, the phenomenon will cause damage to the battery
structure.
6 Nanomaterials for Batteries
6.4.4 Advantages and Disadvantages of Metal-Air Batteries
(1) High specific energy. Since the cathode electrode active material comes from
the outside of the battery, it does not need to occupy the space of the battery.
In the same volume and weight, the metal-air battery can be loaded with more
anode electrode active materials, so that the metal-air battery has a much higher
capacity than the ordinary battery. The specific energy of zinc-air battery theory
is over 1350 Wh/kg, and the actual specific energy is over 1000 Wh/kg. It
belongs to high capacity and high-energy chemical power supply.
(2) Low prices. The resources of some metal (such as zinc, aluminum, and magnesium) are abundant and cheap. Oxygen is derived from the ambient air and is
basically the same as the commonly used lead-acid battery.
(3) Stable performance and stable discharge. Since the cathode catalyst itself does
not change during discharging, and the voltage of zinc electrode is stable, the
change of the voltage is small during discharge.
(4) Excellent storage life. The metal-air battery currently produced is actually a
reserve type battery. Because the sealing process is used in the storage process,
the air hole of the battery is isolated from the outside air. Therefore, the battery
capacity loss is minimal, less than 2% per year.
(5) Safe and reliable, no pollution. The whole process from production to use will
not pollute the environment; it will not pollute the environment, nor will it burn
and explode. It can be called green energy.
Although the zinc-air battery has many advantages mentioned above, there are
still some deficiencies and restricts its large-scale commercial application. The first
problem is self-corrosion of the zinc electrode. Since zinc is thermodynamically
unstable in alkaline solutions, zinc will be accompanied by a small amount of
hydrogen evolution corrosion reaction while discharging in the alkaline electrohydraulic solution. The second problem is carbonation of the air electrode. Since the
battery is discharged for a long time, the reaction product or alkaline electrolyte will
produce a large amount of carbonate when it comes in contact with the outside CO 2 .
When the carbonate is dissolved and saturated, it will precipitate on the upper surface
of the air electrode. This causes the air electrode to become clogged and degrades
in performance and energy, and will no longer work by replacing the zinc negative
electrode with energy. Third, because the air battery is a semi-open system, excessively high or low humidity environment will trigger the phenomenon of “drowning”
or “drying up” of the air electrode, the phenomenon will cause damage to the battery
structure.