Electrolytic capacitor is the generic term for three different capacitor family members:
Tantalum electrolytic capacitors and Niobium electrolytic capacitors
All electrolytic capacitors (e-caps) are polarized capacitors whose anode electrode(+) are made of a special metal on which an insulating oxide layer originates by anodization (forming), which acts as the dielectric of the electrolytic capacitor. A non-solid or solid electrolyte which covers the surface of the oxide layer in principle serves as the second electrode (cathode) (-) of the capacitor.
Due to their very thin dielectric oxide layer and enlarged anode surface electrolytic capacitors have—based on the volume—a much higher capacitance - voltage product compared to ceramic capacitors or film capacitors, but an articulately smaller CV value than electrochemical supercapacitors.