We present a device which is able to separate gases from a gas stream using supercapacitive energy. When a small bias (1 V) is applied to the electrodes and a CO2/N2 mixture is fed through the device, carbon dioxide is selectively adsorbed to those electrodes, and N2 leaves the device in a purified form. When the module is discharged, the CO2 is quantitatively desorbed, and leaves the device in a concentrated form. A single module is able to concentrate CO2 from 15% in the feed gas to 46% in the effluent gas. The energy invested to charge the electrodes can be largely recovered upon discharge. At a charging current of 1 mA an energy recovery rate of 78% can be reached and the associated total energy consumption of the device is 57 kJ mol-1.