Metallic Seals: A Possible Alternative Solution for High Temperature Steam Electrolysis

Abstract

For High Temperature Steam Electrolysis (HTSE), gas tightness largely drives performance and is a critical key to develop this technology. The main difficulties are due to the fact that gas tightness must be achieved at high temperature (~800°C) between metallic components and brittle ceramic materials. The typical sealing solution relies on glass-based seals despite a large number of drawbacks. Metallic solutions have also been studied but without specific developments as they may be too stiff and too hard to be used together with ceramics. A sealing solution based on a specific metallic seal has been developed and is presented here. Using specific tightness tests, it is shown that this new seal remains tight enough during cooling from 800°C to 400°C and that the cell electrolyte can sustain the seating load. This metallic seal offers an alternative solution for HTSE stacks.