How does current relate to electrode area?

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Charles De Raedt

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How does current relate to electrode area?
« on: 26/08/2009 11:30:04 »
Charles De Raedt  asked the Naked Scientists:
   
Dear Chris,

I cant seem to find out the solution to this problem anywhere...You're kinda my last resort...

I'm working on a novel fuel cell/battery and I'm having an Ampere problem. As far as I know, current output is directly proportional to electrode surface area. When I use a 10 square centimetre electrode I get as much current (measured by a digital meter) as when I use a 100 square cm electrode. All other conditions are equal...

Something's not right...What is going on? Help!

Thanks...

cj

What do you think?

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Offline Bored chemist

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How does current relate to electrode area?
« Reply #1 on: 26/08/2009 19:03:24 »
Is the resistance of the electrolyte (or possibly the meter) limiting the current?
Please disregard all previous signatures.

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lyner

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How does current relate to electrode area?
« Reply #2 on: 27/08/2009 22:00:55 »
How does the voltage across the cell vary in each case? You could actually calculate the resistances of the elements in the circuit by looking at the voltage drops around the circuit.
I think the current / area relationship may only be when there is a consistent voltage operating across the cell. You may find the rule works if you keep the operating conditions right.

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Offline Nizzle

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How does current relate to electrode area?
« Reply #3 on: 31/08/2009 11:03:00 »
I don't know much about this subject, but it looks to me like a bottle neck problem.

Or maybe it's a setting on the digital meter that needs adjusting?

Just thinking about the obvious stuff here...
Roses are red,
Violets are blue.
Most poems rhyme,
but this one doesn't