I was looking through chemistry textbooks to find out how to determine how much current a galvanic cell should generate and what affects that current value. However, I did not find anything: textbooks just talk about the EMF of a cell.

I wanted to know what determines how much current a cell generates. Certainly, the amount of electrons produced externally contributes to the current produced by the cell. However, what about internally? Batteries have internal resistance. Is that true of cells too (it should be because batteries are made up of many cells)? What determines amount of internal resistance: does the type of electrolyte(s) affect it. If a cell uses a weak electrolyte (like acetic or carbonic acid) will it cause more internal resistance then if something like sulfuric acid (strong electrolyte) is used?

What if a cell used weak electrolyte as the cathode electrolyte and the strong electrolyte was the anode electrolyte, will that cause more internal resistance due to there being less ions in the cathode compartment as not all of the electrolyte has been dissociated into ions (thus, the cathode cation cannot be reduced)?


1 Answer 1


The current through a cell depends on the plate area. And on the circuit (load) resistance. And on the carrier mobility.

And on the cell voltage -- which will depend on all of the above, which is why a cell EMF is always measured at zero current, open circuit.

The electrode reactions certainly affect the current any cell can support, but your terms "weak" and "strong" are not clear. A "strong" electrode reaction does not mean that you have good carrier mobility through the electrolyte, and good carrier mobility does not meen that you have a good electrode reaction.

Cell current is not a chemical constant: it depends on the physical structure and history of the cell. That is the reason why it is not discussed in chemistry books. People who are trying to make better batteries spend a lot of time working on the carrier mobility, not just the electrode reactions.

  • \$\begingroup\$ what determines carrier mobility because most of the metal electrodes are very good conductors so they should not affect internal resistance as much as the electrolyte solutions, right? \$\endgroup\$
    – user510
    Mar 22, 2016 at 13:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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