Nuclear Production of Hydrogen, Fourth Information Exchange ...

MATERIALS DEVELOPMENT FOR SOEC
Materials development for SOEC*
S. Elangovan, J. Hartvigsen, F. Zhao, I. Bay, D. Larsen
Ceramatec, Inc.
Salt Lake City, Utah, USA
Abstract
Emphasis on energy security issues has brought much-needed attention to economic production of
hydrogen as the secondary energy carrier for non-electrical markets as well as to meet increasing
demand for crude upgrading and desulphurisation. While steam reforming of methane is the current
method of production of hydrogen, the fossil fuel feed consumes non-renewable fuel while emitting
greenhouse gases. Thus, in the long run, efficient, environmentally-friendly and economic means of
hydrogen production using nuclear and renewable energy needs to be developed. Steam electrolysis,
particularly using high temperature ceramic membrane processes, provides an attractive option for
efficient generation of high purity hydrogen.
The high operating temperature that is necessary for an efficient electrolysis process requires the use
of materials that are stable at those temperatures. The materials and fabrication technology that are
used for high temperature solid oxide fuel cells (SOFC) are directly applicable to high temperature solid
oxide electrolysis cells (SOEC). Thus, much of the research work done in the SOFC area is directly
applicable to SOEC technology. Not only the materials set but also the cell and multi-cell stack designs
of SOEC have followed the technology advances of SOFC development.
Ceramatec, in collaboration with Idaho National Laboratory and under the DOE Nuclear Hydrogen
Initiative has tested SOEC cells and stacks of various hydrogen production rates up to 5 000 NL/hr
using SOFC materials set developed at Ceramatec. While the initial stack performance is adequate,
long-term performance stability is not at an acceptable level for commercial hydrogen production.
Several potential causes for degradation were identified; some are common to SOFC device operation
while others are unique to SOEC mode of operation. These range from phase instability of materials
resulting in conductivity degradation, interface delamination, deposition of species at electrochemical
sites to cause electrode poisoning, to oxidation of metallic components in high temperature, high steam
conditions. Under a project funded by the Office of Naval Research, Ceramatec is investigating materials
and process solutions to address many of these issues. The focus area includes evaluation of new
electrode and electrolyte materials, protective coating on metallic interconnects, and joining materials
and techniques to electrically connect a series of alternating cells and interconnects. Test results with
cells and stacks incorporating these changes will be presented.
* The full paper being unavailable at the time of publication, only the abstract is included.
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