(405d) High Temperature Steam Electrolysis for Hydrogen Production: From Materials Development to Stack Operation

High temperature steam electrolysis (HTSE) is one of the most promising options for hydrogen mass production when coupled with nuclear energy. CEA (French Atomic Energy Commission) is carrying out researches in this field, from materials, cells and components developments to stack design and including components and stack testing.

One stack design among those developed at CEA will be addressed in this presentation. This stack is very compact, easy to assemble and simple to operate. Reliability of this design has been demonstrated through several tests of 3 to 5 cells short stacks, cells being commercial 225 cm² electrolyte supported cells. Stacks have been operated in pure water vapor (no hydrogen introduced on the cathode side) at 800 to 825°C. Details about performance and durability of this second stacks will be presented.

Besides these activities on stack design, CEA is carrying out researches on new materials and cells, in order to increase the cell performances and the stack performances. For that purpose, alternative materials are studied, and among them layered perovskites for anodes. These researches, carried out jointly by ICMCB-CNRS and CEA highlighted the great potential of nickelates. It has been shown, on button cells at this stage, that the nickelate oxides formulated Nd2NiO4 and La2NiO4 represent a promising alternative to regular LSM anode (*). Such anodes have been deposited on commercial half electrolyte supported cells, and performances up to three times higher have been obtained when operated in HTSE mode compared to an identical commercial cell containing the same cathode and electrolyte but with a conventional LSM anode. Details about the performance of this new alternative anode material will be given in this presentation.

(*) Patent CNRS - EDF (F) "Procédé et dispositif d'électrolyse de l'eau comprenant un matériau oxyde d'électrode particulier", P. Stevens, C. Lalanne, J.M. Bassat, F. Mauvy et J.C. Grenier. France brevet : FR 2872174 2005-12-30