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The key technical challenges that fuel cell developers need to address are performance, durability, and cost. All three need to be achieved in parallel; however, there are often competitive tensions, e.g., performance is achieved at the expense of durability. Stability and resistance to degradation under prolonged operation are key parameters. There is considerable interest in developing new cathodes that are better able to function at lower temperature to facilitate low cost manufacture. For anodes, the ability of the solid oxide fuel cell (SOFC) to better utilize commonly available fuels at high efficiency, avoid coking and sulfur poisoning or resistance to oxidation at high utilization are all key. Optimizing a new electrode material requires considerable process development. The use of solution techniques to impregnate an already optimized electrode skeleton, offers a fast and efficient way to evaluate new electrode materials. It can also offer low cost routes to manufacture novel structures and to fine tune already known structures. Here impregnation methodologies are discussed, spectral and surface characterization are considered, and the recent efforts to optimize both cathode and anode functionalities are reviewed. Finally recent exemplifications are reviewed and future challenges and opportunities for the impregnation approach in SOFCs are explored.

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Excellent area-specific-resistance (ASR) values have been exhibited by cathode materials with a Sr-doped layer perovskite type structure and therefore show themselves to be possible candidates for intermediate-temperature-operating solid oxide fuel cell (IT-SOFC, 600–800°C) applications. SmnormalBa0.5normalSr0.5normalCo2normalO5+δ (SBSCO) electrode was sintered onto 10mol% gadolinia-doped ceria ( normalCe0.9normalGd0.1normalO2 , CGO91) at 1000°C to form symmetrical cells and exhibited an ASR value of 0.092Ωcm2 at 700°C . The lowest ASR value was observed when the composite cathode of 50wt% of SBSCO and 50wt% of CGO91 (SBSCO50) was used in conjunction with an interlayer of CGO91 applied between the electrode and 8mol% normalY2normalO3 stabilized ZrnormalO2 electrolyte. These were 0.12Ωcm2 at 600°C and 0.019Ωcm2 at 700°C , respectively. The coefficient of thermal expansion (CTE) of SBSCO was 21.9×10−6normalK−1 at 700°C . However, the CTE of the composite cathode of SBSCO50 was shown to be 13.6×10−6normalK−1 at 700°C , this being more compatable with the other components within the cell.

When a jack-up spudcan foundation is installed on seabeds consisting of a sand layer overlying soft clay, the potential for 'punch-through' failure exists. This happens as a result of an abrupt reduction in bearing resistance when the foundation punches a block of sand into the underlying soft clay in an uncontrolled manner. This paper details an extensive series of 30 tests of flat circular and spudcan foundations continuously penetrated through samples of sand overlying clay, and performed under relevant stress conditions using a drum centrifuge. The large testing area of the drum centrifuge was used advantageously to produce test results that could be compared directly with tests covering a sand thickness over foundation diameter of 0 . 21 to 1 . 12. Results from retrospective finite-element analysis of the experiments are also described, with back-calculated values of the stress-level-dependent friction and dilation angles in the sand during peak penetration resistance shown to fit correlations in the literature. The back-analysis showed that larger values of peak resistance gave lower friction and dilation angles, which is consistent with gradual suppression of dilatancy under high confining stress. When compared with published results from visualisation experiments, the finite-element analysis showed a similar failure mechanism during peak resistance, with a frustum of sand forced into the underlying clay at an angle reflecting the dilation in the sand.

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Assessment of the risk of punch-through failure of spudcan foundations on sand overlying clay requires prediction of the full penetration resistance profile, from touchdown and through punch-through to equilibrium of the vertical resistance at depth in the underlying clay layer. This study uses the Coupled Eulerian–Lagrangian approach, a large deformation finite element analysis method, to model the complete penetration resistance profile of a spudcan on sand overlying clay. The sand is modeled using the Mohr–Coulomb model, while the clay is modeled using a modified Tresca model to account for strain softening. The numerical method is then used to simulate a series of spudcan penetration tests, performed in a geotechnical centrifuge, on medium dense sand overlying clay. The punch-through behavior observed in the experiments is replicated, and the penetration resistance profiles from numerical analyses are generally a reasonable match to the experimental measurements. The influences of the sand layer height to foundation diameter ratio, sand–clay interface shear strength, and strength gradient in clay on the penetration resistance profiles are explored in a complementary parametric study. The penetration resistance in the underlying clay layer is well predicted using a simple linear expression for the bearing capacity factor for the spudcan and underlying sand plug. This expression is combined with an existing failure stress dependent model for predicting peak resistance to form a simplified method for prediction of the full penetration resistance profile. This new method provides estimates of the vertical penetration that the spudcan will run during the punch-through event. It is validated against both medium dense and dense sand centrifuge tests.

The electrochemical characteristics of the samarium and strontium doped layered perovskite (SmBa1−x Sr x Co2O5+δ, x = 0.5) have been investigated for possible application as a cathode material for an intermediate temperature-operating solid oxide fuel cell (IT-SOFC). The cathodic polarization of single-phase and composite cathodes with 10 mol % gadolinia-doped ceria (Ce0.9Gd0.1O2−δ, CGO91) shows that a weight ratio between SmBa0.5Sr0.5Co2O5+δ (SBSCO) and CGO91 of 1:1 (50 wt % SBSCO and 50 wt % CGO91, SBSCO:50) gives the lowest area specific resistance (ASR) of 0.10 Ω cm2 at 600 °C and 0.013 Ω cm2 at 700 °C. The maximum and minimum electrical conductivity in SBSCO are 1280 S cm−1 at 50 °C and 280 S cm−1 at 900 °C, with the influence of oxygen partial pressure indicating p-type conduction. The maximum power density of SBSCO:50 in an anode supported SOFC was 1.31 W cm−2 at 800 °C and 0.75 W cm−2 at 700 °C.