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Solid oxide fuel cells are characterized by a high efficiency for converting chemical energy into electricity and fuel flexibility. This research work focuses on developing durable and efficient anodes for solid oxide fuel cells (SOFCs) based on exsolving nickel from the perovskite structure. A-site-deficient La- and Ni-doped strontium titanates (La0.2Sr0.7Ti0.95Ni0.05O3−δ, LSTN) were synthesized using four different techniques and mixed with Ce0.8Gd0.2O2−δ (GDC) to form the SOFC anode. The synthesis routes of interest for comparison included solid-state, sol-gel, hydrothermal, and co-precipitation methods. LSTN powders were characterized via XRD, SEM, TPR, BET and XPS. In situ XRD during reduction was measured and the reduced powders were analyzed using TEM. The impact of synthesis route on SOFC performance was investigated. All samples were highly durable when kept at 0.5 V for 48 h at 800 °C with H2 fuel. Interestingly, the best performance was observed for the cell with the LSTN anode prepared via co-precipitation, while the conventional solid-state synthesis method only achieved the second-best results. [ABSTRACT FROM AUTHOR]

Next-generation solid oxide fuel cells (SOFCs) require rapid start up times to fit the requirements for automotive and aviation industries. However, rapidly started SOFCs suffer from degradation and failure of the fuel cell components. This is due to the difference in the thermal expansion coefficients (CTE) between the different components of the fuel cell, and especially the low thermal shock resistance (TSR) of the ceramic electrolyte. Introducing multi-phase materials to SOFC components can help manage the difference in CTE and improve the thermal shock resistance where it is lacking. In this research, we aim to change the electrolyte's CTE. This is made possible by incorporating secondary phases, with a negative thermal expansion (NTE) coefficient. These can be formed during the sintering process by adding tungsten oxide to the powder. The produced composite electrolytes showed reduced effective CTE in the operating temperatures and an increase in the thermal shock resistance. Introduction of varied amounts of such a secondary phase, could allow tailoring of the CTE and therefore improving the durability of the SOFC in rapid start up times. Image 1 • Using a sol-gel approach and a solid-state synthesis to obtain a ceramic composite. • Investigating a ceramic composite of yttrium stabilized zirconia and Y 2 W 3 O 12. • Lower thermal expansion coefficient effect on the composite's thermal shock resistance. • Testing the composite's ionic conductivity in against a solid oxide fuel cell electrolyte. [ABSTRACT FROM AUTHOR]