Phys.org has a nice snippet on the Gouy-Chapman theory that describes how charge is distributed in electrolysis, but now 40-50 years later they found that the description isn't really correct. They found that the double layer could be bigger or smaller than expected and it has dependencies on the size of the ion molecule and the electrode materials which can affect the electrochemistry of some reactions.
It's a nice little read at https://phys.org/2022-01-century-old-electrochemistry-law.amp .
