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Aluminium oxidation

  1. Oct 10, 2016 #1
    I have watched many videos of aluminium air batteries and it got me wondering. Could this same process work if you stored the aluminum in vacuum and exposed it to oxygen? For example:

    A high surface area aluminium plate is in a glass bulb under high vacuum. A copper lead connects to the aluminium to a load. If we break the bulb the aluminium will rapidly oxidize. How do you close the circuit? I know you could ground it but what about in aportable application? Reusability and controlled current flow are of no concern.
     
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  3. Oct 10, 2016 #2

    Bystander

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  4. Oct 10, 2016 #3

    anorlunda

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    My hearing aids run on zinc-air batteries, which are analogous. They are tiny. They have the strange property for batteries that once exposed to the air, they run out in 8 days regardless of how much electric power is supplied to the load. Full load, zero load, still lasts 8 days.
     
  5. Oct 10, 2016 #4

    Borek

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    In what you described the circuit is already closed.

    Whole trick with every battery is to have both half reactions separated so that electrons can flow through an external circuit, instead of jumping from one atom/ion/molecule to another directly.
     
  6. Oct 10, 2016 #5
    If we released pure oxygen inside an aluminium sphere, a charge would develope on its surface correct?
     
  7. Oct 10, 2016 #6
    I guess a better question would be; when 1 side of an aluminium plate is oxidized, does a charge develop on the opposite side?
     
  8. Oct 10, 2016 #7

    Borek

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    No. I told you how it works. Please read any general chemistry book on redox reactions and cells and you will see what it is all about, right now you are just wild guessing.
     
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