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I'm 15 and recently started electronics and I just had a question about batteries.

(I've been told by people on physics stack exchange to come here to have my question answered).

From what I understand and according to the videos I've watched, a battery creates a potential difference (votlage) by accumulating more high concentration the negative plate than the positive plate. Therefore the higher concentration of electrons, the higher potential difference (voltage).

Could someone tell me if this is correct?

Thanks

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Development of a potential difference when you connect two dissimilar metals "dipping" in their own solutions is another fundamental phenomenon exhibited by matter. It is a property of matter and batteries utilize this very phenomenon. Perhaps a hardcore physicist can tell you why do you have a mass, in the same way, this is a pure theoretical problem of physics as to why this happens. It just happens and it is related to the structure of matter (in fancier terms ... Fermi levels).

Suppose you have two different metal pieces (= two materials having different electronic energy levels) dipping in their respective solutions of ions. Now you connect them with a piece of wire. Since, by definition, there are two different materials, one of them would have electrons at a higher energy level than the other. I mean there must a be difference in the energies of electrons in material A vs. material B, since these are two different elements. Since the metals are connected, it is one conducting system. The electrons would travel from a higher energy to lower energy in this system. What is the flow of electrons in unit time? It is called current. Your battery is ready.

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You identify a system where electron transfer is spontaneous, say, from R to O. This is a redox reaction with a reductant (R) and an oxidant (O).

$$\ce{R + O -> R+ + O-}$$

Now if you are able to physically separate R and O and provide a pathway just for the electrons, then you can harness the flow of electrons in the wire.

You're not really going to get any significant concentration of electrons because any accumulation of charge immediately leads to a high energy system due to charge-charge repulsion. But a higher concentration of either reductant or oxidant should increase the potential difference for thermodynamic reasons.

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