Electrolyte. The electrolytic capacitor got its name from the electrolyte, the conductive liquid inside the capacitor. As a liquid it can be adapted to the porous structure of the anode and the grown oxide layer with the same shape and form as a "tailor-made" cathode.

What liquid is in capacitor?

Various liquid electrolytes are used in electrolytic capacitors today. Electrolytes containing ethylene glycol (EG) or boric acid are used mainly in medium to high-voltage electrolytic capacitors at temperatures of up to 85°C.

Can a capacitor leak fluid?

So, to get back to your question: even though it may seem like it, by far the most important reason that electrolytic capacitors seem to leak more is that they simply have more capacitance and, by association, larger surface areas and thinner insulators which both contribute to higher leakage.