Sodium-Modulated, AMTEC Electrode Deposition

A key component in the Alkali Metal Thermal to Electric Converter (AMTEC) is the electrode that is generally sputter deposited on the beta"-alumina solid electrolyte (BASE). Electrode deposition, as it is now practiced however, is a random process that covers active sites on the BASE and places many electrode pore openings at inactive sites. This proposal describes a novel fabrication process for improving electrode components of AMTEC cells. Exchange current densities will be increased by 500% at the BASE/electrode interface by selectively exposing all of the active sodium sites to the 3-phase electrode-BASE-sodium vapor boundary. The new process will selectively deposit the electrode only on the inactive sites of the BASE using the charge sensitive properties of the BASE to control where the electrode is deposited. This leaves the active sites of the BASE conduction plane at the electrode edges. This process will use the common electrode materials, Mo, W(Rh,Pt) and/or TiN. If successful, this process can increase the power output of an AMTEC cell by 50% without increasing the size or weight