Device designs are presented that include a cathode subassembly for protecting the device from unwanted discharge, and aiding in alignment of the cathodes and anodes within a device. A device includes a conductive anode, a dielectric material disposed on a surface of the conductive anode, a conductive cathode, and an electrolyte disposed between the anode and the cathode. The conductive cathode is sandwiched between two separator sheets, the two separator sheets being adhered together at a peripheral edge in an area outside of a perimeter of the conductive cathode.