Supercapacitor is a type of electrolytic (polarized) capacitor that can provide extremely high capacitance values in relation to physical size and low rated voltage. The rated voltage of a single device is usually low, but some products connect multiple devices in series to achieve a higher rated voltage. Compared with other electrolytic capacitors, the losses of supercapacitors are generally higher, but lower compared with electrochemical batteries. Therefore, they are often used as alternatives to electrochemical batteries, especially in applications that require high cycle times or power densities.