Tantalum

Tantalum capacitors are a type of electrolytic capacitor. They are polarized, having anode, cathode and electrolyte. The anode is made up of a small piece of tantalum metal insulated by a thin oxide layer, which creates the dielectric. This thin oxide layer means that a much higher capacitance level can be achieved per volume. Tantalum capacitors also offer better long-term stability, lower ESR and lower leakage than aluminum electrolytic types.