Optimisation of Metallic Interconnects for Hydrogen Production by High Temperature Water Vapour Electrolysis

Abstract

For economical and environmental reasons, hydrogen is considered as a major energetic vector for the future. Hydrogen production via high temperature water vapour electrolysis (HTE) is a promising technology. A major technical difficulty related to high temperature water vapour electrolysis is the development of interconnects working efficiently for a long period. Working temperature of 800°C enables the use of metallic materials as interconnects. Chromia forming alloys are among the best candidates. The interconnect material chosen in the present study is a ferritic stainless steel with 18% chromium content. High temperature corrosion resistance and electrical conductivity of the alloy was tested in both cathode (H2/H2O) and anode (O2/H2O) atmospheres. Corrosion products were then characterized by SEM-EDX and XRD. Moreover chromium evaporation measurements were carried out under anode atmosphere.

Effect of Coatings on a Commercial Stainless Steel for SOEC Interconnect Application in Anode Atmosphere

“…For isothermal ageing tests, the samples were placed in a horizontal furnace for 100h. ASR measurements were performed in-situ during 100 hours by using a 4-point set up (5,15). Prior to conductivity measurements a pre-oxidation of 100 hours at 800°C in 95%O 2 -5%H 2 O is performed before the application of a Pt paste, necessary to ensure the good electrical contact during the measuring.…”

“…In previous studies, the high temperature corrosion behaviour and the electrical conductivity of the K41X (AISI 441) were investigated in both anode (O 2 -H 2 O) and cathode (H 2 -H 2 O) atmosphere at 800°C (5,6). Moreover, chromium evaporation measurements were performed in anode atmosphere.…”

Surface degradation of three Cr-containing cobalt-based alloys exposed to pure water vapour at 900°C

“…Water vapour is often present in the mixtures of the gaseous environments in which refractory alloys work, e.g. super-heater and re-heater tubes in supercritical units [7] or interconnects for hydrogen production [8]. These refractory alloys are frequently stainless steels [9] or nickel-based superalloys [10].…”