The Electrolytic Capacitors are the capacitors which indicate by the name that some electrolyte is used in it. They are polarized capacitors which have anode (+) and cathode (-) with particular polarities.
A metal on which insulating oxide layer forms by anodizing is called as an Anode. A solid or non-solid electrolyte which covers the surface of the oxide layer, functions as a cathode. The Electrolytic Capacitors have much higher Capacitance-Voltage (CV) value than the others, due to their larger anode surface and thin dielectric oxide layer.