I posted an explanation here using a lead-acid battery cell as an example. You can have a look and see if that answers some of your questions: https://www.reddit.com/r/explainlikeimfive/comments/17mm7h5/eli5_how_does_a_battery_work/
Essentially, these are corrosion reactions that either leave superfluous electrons or require extra electrons in order to complete, and only by transferring the electrons from one electrode to the other through a conductor can the reactions go forth.
Latest Answers