This paper reviews carbon-based nanostructured materials as electrodes in electrochemical capacitors and distinguishes the carbon-based electrode materials according to their primary applications. They are broadly discussed and categorized into three groups based on their specified energy storage device applications: (1) industrial and stationary applications, (2) automotive and transportation applications, and (3) portable and personal electronics applications. Different carbon-based nanostructured electrodes were discussed from different perspectives, such as energy density, power density, reliability, safety, and cost. The basic principles, characteristics, various performance, and features of the supercapacitors to meet the requirements of different applications were analyzed. The future trend of electrochemical capacitors was discussed.