双电层电容器（EDLC）有时也称为电双层电容器，或超级电容器，是拥有高能量密度的电化学电容器，比传统的电解电容容量高上数百倍至千倍不等。

一个标准电池大小的电解电容电容为几十微法拉，但同样大小的EDLC的则可以达到几法拉，差别可达五个数量级。截至在2010年，最高商业化双电层电容器的能量密度为30 W⋅h/kg (0.1 MJ/kg)。高达85 W⋅h/kg的能量密度已在室温实验室实现，但仍然比锂电池低。

2011年，在实验室的双电层电容器的能量密度提高了一个数量级。EDLC的价格亦正在下降：在2000年成本为5000美元的3 kF电容在2011年只需50美元。

A supercapacitor (SC) (sometimes ultracapacitor, formerly electric double-layer capacitor (EDLC)) is a high-capacity electrochemical capacitor with capacitance values much higher than other capacitors (but lower voltage limits) that bridge the gap between electrolytic capacitors and rechargeable batteries. They typically store 10 to 100 times more energy per unit volume or mass than electrolytic capacitors, can accept and deliver charge much faster than batteries, and tolerate many more charge and discharge cycles than rechargeable batteries. They are however 10 times larger than conventional batteries for a given charge.