1
$\begingroup$

Can alumina behave as a solid electrolyte for oxygen ions? Could a cell be constructed with an oxygen cathode and a molten aluminum anode producing more alumina? Would the resulting alumina deposit on the electrolyte? Would it be crystalline?

$\endgroup$
2
$\begingroup$

Alumina is one of the most abundant compounds on Earth. If it would be also a solid electrolyte for oxygen ions, why in the world would anyone go into the trouble of dealing with the whole $\ce{Y2O3/ZrO2}$ thing? No, alumina doesn't and can't behave like that. Its oxygen ions are held in place pretty tightly.

Some forms of alumina may serve as conductors of $\ce{Na+}$ and similar cations, but that's another story.

$\endgroup$
  • $\begingroup$ You might use use yttria-stabilized zirconia because alumina is a poor ionic conductor. Ice is a proton conductor, but nobody uses it as such. Ionic conductivity increases with temperature. The melting point of alumina is over 2000°C. Are you sure there's no ionic conduction? $\endgroup$ – Pence128 Oct 9 '15 at 23:57
  • $\begingroup$ Why, there might be some, just not enough to make a real thing out of it. I should have said "If it would be also a good solid electrolyte..." $\endgroup$ – Ivan Neretin Oct 10 '15 at 0:07
  • $\begingroup$ If you read my question carefully, you'll note that I never asked if alumina is a good solid electrolyte, only if it is one. The popularity of zirconia and ceria based electrolytes in SOFCs proves it doesn't make for a practical electrolyte if the intent is to generate electricity. $\endgroup$ – Pence128 Oct 10 '15 at 0:29
  • $\begingroup$ Hm... that's right. It turns out that in fact I answered another question, albeit somewhat related to yours. Well, let it remain this way. $\endgroup$ – Ivan Neretin Oct 10 '15 at 0:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.