« on: 24/07/2023 20:46:39 »
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I still don't understand fully.
So both metals are neutral, but have tendency to release or gain electrons.
While it is possible to use two neutral metals with wildly different electronegativities (like aluminum and palladium), this is not always the case (see my previous post in this thread).When connected together, their pairing tendency moves electrons from one to the other.
For the electrons to move, we need to provide a path, which we do via? What are the necessary characteristics of that path? Doesn't simple water do?
A wire provides the path for electrons to move. Water (or other highly polar liquids, or ionomers etc.) allow ions to move.When electrons move, they generate positive and negative charged metals that create a potential difference.If ions were not allowed to flow then yes, the there might be a very brief spike in current when the terminals are connected by a wire, but the voltage would drop to zero when the batteries internal electric field cancels out the inherent electron affinities of the different metals (and/or ions). But, when ions are able to move within the battery, their motion will keep the internal electric field very small (zero internal field, for perfect ion mobility), allowing the voltage of the battery to remain constant until one end runs out of electrons to give, or the other end runs out of space to accept electrons, or there are no more mobile ions. (to first approximation--the voltage will actually decrease slightly as one or more of the limits is approached, rather than suddenly dropping from 100% to 0%--but this is a complication you can ignore until you feel more comfortable with the "ideal" case. When ready for this complication, you can read about it here: https://en.wikipedia.org/wiki/Nernst_equation)
What happens as the electrons move apart from charging the metals? So that the battery capacity drops yet the voltage stays the same?