High Performance SOFC Cathode Prepared by Infiltration of Lan + 1NinO3n + 1 (n = 1, 2, and 3) in Porous YSZ

La 2 NiO 4 , in Ruddlesden-Popper series, has received widespread attention as a promising cathode material by reason of its favorable properties for realizing high performance of intermediate temperature solid oxide fuel cells (IT-SOFCs). La 2 NiO 4 -yttria-stabilized zirconia (YSZ) composite is chosen as a base material and is prepared by infiltration of La 2 NiO 4 oxide into porous YSZ. The effects of increasing n in La n + 1 Ni n O 3 n + 1 -YSZ composites are evaluated in terms of structure, electrical characteristics, and electrochemical performance for application in IT-SOFCs. The electrical conductivities of La n + 1 Ni n O 3 n + 1 -YSZ composites ( n = 1, 2, and 3) are improved with the increasing number of n in air. Anode-supported single cells based on YSZ electrolyte with La n + 1 Ni n O 3 n + 1 -YSZ composites ( n = 1, 2, and 3) are fabricated by the infiltration method for evaluation of the cell performance. The maximum power density obtained for a single cell with the La 2 NiO 4 -YSZ composite is 0.717 W cm −2 at 750°C with humidified H 2 (3% H 2 O) as a fuel. La 3 Ni 2 O 7 -YSZ and La 4 Ni 3 O 10 -YSZ composites also achieved power densities of 0.754 and 0.889 W cm −2 , respectively, under the same conditions. Considering its high electrical conductivity and extended electrochemical reactive sites, La 4 Ni 3 O 10 -YSZ composite ( n = 3) is a promising candidate among Ruddlesden-Popper series for a cathode material in IT-SOFC applications.