Complex sentence: The first industrial realized electrolytic capacitors consisted out of a metallic box used as cathode, filled with a borax electrolyte solved in water, in which a folded aluminum anode plate was inserted.
Split into simpler sentences: The first industrially realized electrolytic capacitors consisted of a metallic box used as the cathode. It was filled with a borax electrolyte dissolved in water, in which a folded aluminum anode plate was inserted.