电解电容是一种按结构、制作工艺划分的电容种类。通常，电解电容是一种有极性的电容。电解电容的阳极采用可钝化的金属材料，比如铝、钽、铌、钛等；介电材料为阳极金属材料表面生成的致密氧化物薄膜；电解电容的阴极材料为电解质。电解电容的主要特点是，在相同的体积下，可以得到比普通电容大得多的电容量（假设耐压相等）。

电解电容所用的电解质型态，有以下种类：

Electrolytic capacitor is the generic term for three different capacitor family members:

All electrolytic capacitors (e-caps) are polarized capacitors whose anode (+) is made of a particular metal on which an insulating oxide layer forms by anodization, acting 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.