Batteries have a circuit which looks like this :
The electrons go around the circuit and then return through the battery where they get charged again and flow around.
My issue is, what about alternating current? For example main power, simply it looks like this (pretend the globe is in your house)
Do the electrons return or go to the Earth? And how does it work when there is a short-circuit? Why does it go to the Earth instead of the neutral? Is it because of the lower electronegativitiy?