A question about the function of electrolyte in electrolytic caps
The 'electrolytic capacitor' is not called that because it contains an electrolyte. It's called that because a key step in its manufacture is the formulation of thin layer of dielectric oxide on the positive aluminium plate by electrolysis.



The electrolytic capacitor gets its large capacitance from the very thin dielectric layer and the large area of the roughened plate. Without a liquid, the air or vacuum between the plates would cause a huge loss in capacitance. The electrolyte (that is, conductive liquid) fills the interstices of the anode, and is effectively the cathode to the thick oxide layer on the anode.