Novel La2NiO4+δ and La4Ni3O10−δ composites for solid oxide fuel cell cathodes

Ruddlesden-Popper phases of the formula (LaNiO3)nLaO are potential materials for intermediate-temperature solid oxide fuel cell cathodes. The n = 1 phase La2NiO4+δ is known to have good ionic conductivity but its performance as a single-phase cathode is limited by its electronic conductivity. The n = 3 phase La4Ni3O10−δ is known to have good total conductivity but has been little-explored as a cathode. In this study we explore composite electrodes of these two materials with a view to taking advantage of their complimentary properties. The performance of these electrodes is compared to that of the single-phase end-members and is found to be improved above 600 °C. A 50:50 wt.% La2NiO4+δ:La4Ni3O10−δ mix gave the best performance and represents best-in-class for these materials.