An electrical energy storage device includes a first electrode; a second electrode; a separator; and an electrolyte; where the separator is an electronic insulator; the separator is positioned between the first and second electrodes; the separator includes a first surface proximal to the first electrode and a second surface proximal to the second electrode; the separator is configured to support an electric double layer at the first surface, the second surface, or at both the first surface and the second surface; and the device is an electrical energy storage device.