Electrochemical supercapacitors (ES) are urgently needed as components in many advanced power systems requiring high power density. A new wave of interest in electrochemical supercapacitors is related to the development of electric and fuel cell vehicles. ES allow significant energy savings and optimize operation of engines, batteries and fuel cells. Buses and cars need efficient energy storage devices, which accumulate braking energy to be reused in the next acceleration phase. Energy storage mechanisms of electrochemical supercapacitors include double layer capacitance arising from the charge separation at an electrode/electrolyte interface and pseudo capacitance arising from reversible Faradaic reactions. Research has been focused on the development of electrode materials, which have high specific capacitance in various electrolytes. To realize a high capacitance, electrode materials are fabricated in a three-dimensional matrix form to achieve a high surface area. Novel electrochemical technologies are currently under development for the fabrication of nanostructured oxides and nanocomposites for applications in supercapacitors and hybrid supercapacitor-battery devices. An advanced testing facility is used for the investigation of power-energy characteristics and charge storage mechanisms.