1. Towards durable and efficient high temperature steam electrolysis:
material improvements in the RelHy project
Florence Lefebvre-Joud1*, Annabelle Brisse2, Jacob Bowen3, Bert Rietveld4, Nigel Brandon5
1 Commissariat à l’Energie Atomique Grenoble - 2 European Institute for Energy Research
3 Danish Technical University - 4 Energy Research Centre of the Netherlands
5 Imperial College London
High temperature electrolysis has been demonstrated in the 80’s by Dornier using tubular
ceramic cells wit YSZ1 as electrolyte, Ni-YSZ as hydrogen electrode (cathode) and LSM2 as
air electrode (anode) [1,2]. In the recent Hi2H2 project [3], up-graded SOFC cells, single
repeating units (SRUs) and short stacks have been operated in the electrolysis mode. The
obtained results, in complete agreement with North American [4] and Japanese [5] studies,
confirm the high potential of Solid Oxide Electrolyser Cell (SOEC) technology. Hydrogen
production rates up to 0.1 gH2cm-2 hr-1, corresponding to 3.6 Acm-2 at 950°C at the cell level,
have been achieved [6,7].
However, these high performances are associated with too high degradation rates
compromising market entrance [8, 9]. The RelHy project [10] aims at identify and overcome
these degradation mechanisms. For such purpose, several instrumented SRUs and short stacks
are going to be operated in parallel according to a defined common testing protocol with
selected interconnect, protective layer, contact layer, sealing and cell materials. These tests
are complemented by extensive post-test characterisations and are simulated by FE-CFD
model integrating inputs from micro-modelling in order to take into account microstructure
evolution effects in all SRU’s materials.
First results obtained with traditional interconnect, protective layer, contact layer, sealing and
cell materials are presented and discussed.
1 – W. Dönitz and R. Schmidberger, Inter. J. Hydrogen Energy, 7, 321, (1982).
2- K.H. Quandt, R. Streicher « Concept and design of a 3.5MW pilot plant for high temperature
electrolysis of water vapor », Int. J. Hydrogen Energy, Vol. 11, no. 5, pp 309-315 (1985).
3- Hi2H2 Final report – Publishable executive summary - www.Hi2H2.com
4- J.E. O’Brien, C.M. Stoots, J.S. Herring, P.A. Lessing, J.J. Hartvigsen, S. Elangovan “Proceedings
of ICONE12”, 12th International Conference on nuclear Engineering, Virginia, USA, (2004)
5- H. Uchida, Electrochemical and Solid State letters, 7, A500, (2004).
6 - M. Mogensen, S.H. Jensen, A. Hauch, I. Chorkendorff, and T. Jacobsen. Proceedings 7th European
SOFC Forum, Lucerne, (2006).
7- S.H. Jensen,, P.H. Larsen, and M. Mogensen, Inter. J. Hydrogen Energy, (submitted), (2007).
8- A. Hauch, S.H. Jensen, M. Mogensen, and S. Ramousse, “Performance and durability of Solid
oxide Electrolysis cells” S. J. Electrochem. Soc., 153, (9),1741, (2006).
9- J. Schefold, M.J .Garcia, A. Brisse, D. Pedrenis, M. Zahid, “Hydrogen Production by High
temperature water Electrolysis, 8th European SOFC Forum, Lucerne, (2008).
10 – www.relhy.eu
* corresponding author
1
Yttria stabilized zirconia
2
Strontium doped Lanthanum Manganite