alkaline hydrogen-fuel cell

[patrickthai]

whats the difference between a normal one? And whats the difference in equations?

[jimmy999]

An alkaline fuel cell will have ions as the electrolyte, in which case you'd use the equation in your data book containing hydroxide ions.

An acidic fuel cell will use ions as it's electrolyte.

There is no normal hydrogen fuel cell as each one requires an electrolyte to allow ions to move. There is a ceramic electrolyte which tends to use ions as the electrolyte, hence you will use this in your equations instead of the hydronium/hydroxide ions

[patrickthai]

can ya give me example half equations for alkaline hydrogen fuel cells and acidic hydrogen fuel cell? Im not really gettin it but improved knowledge abt it.

[Mao]

H2/O2:

Acidic electrolyte
H2 --> 2H+ + 2e
O2 + 4H+ + 4e --> 2H2O

Alkaline (hydroxide) electrolyte
H2 + 2OH- --> 2H2O + 2e       [compare this to the above, we have added 2 OH- to both sides to neutralize the acid]
O2 + 2H2O + 4e- --> 4OH-     [also compare this to above, 4 OH- has been added to both sides, and some H2O cancelled out]

Solid Oxide (O^2-) electrolyte
H2 + O^2- --> H2O + 2e  [compare this to the acid, O^2- is a strong base that can accept 2 H+, hence 1 O^2- is added to both sides to neutralize the acid]
O2 + 4e- --> 2O^2-        [compare this to the acid, 2 O^2- has been added to neutralize the acid, and some H2O cancelled]

[simpak]

I actually always die when this happens.
If we get asked on the exam; ffff.
Tomorrow morning, I'm just going to practice writing half equations in an alkaline environment.
Watch me!

Thanks Mao.

[patrickthai]

mao u make it look so easy.
Thanks heaps.