Practical implementation of direct HC SOFCs faces major problems arising from the fact that the anode materials operate under severe conditions leading to low activity towards reforming and oxidation reactions, fast deactivation due to carbon deposition and instability due to the presence of sulphur compounds in the feed.
T-CELL approach: concept and key objectives of the project
T-CELL introduces a novel electrochemical approach aimed at tackling SOFC degradation problems. The principal objective of the project is to study and apply a triode architecture and operation concept for cell and stack design. This will be accomplished by means of a third electrode, driven by an auxiliary circuit, which is run in electrolytic mode. In this way the anode or cathode of the cell can be forced to operate at controlled potential differences that are inaccessible under standard operation. The application of this triode concept SOFC can significantly decrease anodic and cathodic polarization losses. Triode operation is advantageous when a significant anodic overpotential is present, as is expected to be the case with natural gas and gasoline-fuelled SOFCs. Another entirely new possibility offered by triode operation is that of inducing potential modulations that (i) allow electrocatalyst operation under potential difference conditions that are inaccessible in conventional operation, and (ii) force oxygen anion migration to the catalyst surface. Both phenomena are expected to be important in controlling the rate of carbon deposition and sulphur poisoning. In terms of materials to be employed, advanced Ni-based cermet anodes modified via doping with a second or a third metal will be developed and evaluated, in synergy with the triode operation, for their effectiveness in controlling the rate of both carbon deposition and sulphur poisoning under steam or dry reforming conditions.