Bulk expansion of the anode upon oxidation is considered to be responsible for the lack of redox stability in high-temperature solid oxide fuel cells ͑SOFCs͒. The bulk expansion of nickel-yttria stabilized zirconia ͑YSZ͒ anode materials was measured by dilatometry as a function of sample geometry, ceramic component, temperature, and temperature cycling. The strength of the ceramic network and the degree of Ni redistribution appeared to be key parameters of the redox behavior. A model of the redox mechanism in nickel-YSZ anodes was developed based on the dilatometry data and macro-and microstructural observations.

Abstract. Methane steam reforming has been studied over a range of nickel/ceria-gadolinia cermet anodes, over the temperature range 500-700 ~ appropriate for intermediate temperature ceriagadolinia based SOFCs. The influence of operating temperature and methane/steam ratio on the reforming characteristics, methane conversion and product selectivity, and the carbon deposition on the anode during reforming, has been determined for each anode.Nickel/ceria powders made from gas atomised intermetallic precursors have been studied as potential anode materials for intermediate temperature ceria-gadolinia based SOFCs running on natural gas. The powders have been characterised structurally and evaluated for their methane reforming characteristics and their resistance to carbon deposition during internal reforming, especially at low steam/methane ratios, over the relevant operating temperature ranges of ceriagadolinia based SOFCs. Their performance has been compared to conventionally prepared anodes and anodes generated from cast alloys, with very favourable results.

The limitations of the current state of the art Ni‐YSZ cermet anodes with respect to Redox stability, coking and sulphur tolerance are well acknowledged. A material which mitigates all or even some of these issues would be of great importence for the continued development of robust SOFC systems. One such promising material system is based around the perovskite (La,Sr)Cr0.5Mn0.5O3 (LSCM). In this paper, some aspects of the work, carried out to integrate LSCM anodes into the IP‐SOFC, are described. The intricacies of the introduction of a new material into an existing stack design concept are considered and how this impacts the performance and requirements of adjacent materials. In the case of the LSCM integration, at least as much work has gone into the development of these layers as into the anode itself. In particular, the design of a current collector to optimise both the conductivity across the layers and the adhesion to the anode has proved to be a challenging task within the normal design constraints of the IP‐SOFC. Initial perfomance of around 75 mW cm–2 in a stack repeat unit test is encouraging and initial analysis has suggested that further development of the current collecting microstructure will confer significant performance improvements.

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