La2NiO4, 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). La2NiO4-yttria-stabilized zirconia (YSZ) composite is chosen as a base material and is prepared by infiltration of La2NiO4 oxide into porous YSZ. The effects of increasing n in La-n (+) 1NinO3n (+ 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 + 1NinO3n (+ 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 Lan + 1NinO3n (+) (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 La2NiO4-YSZ composite is 0.717 W cm(-2) at 750 degrees C with humidified H-2 (3% H2O) as a fuel. La3Ni2O7-YSZ and La4Ni3O10-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, La4Ni3O10-YSZ composite (n = 3) is a promising candidate among Ruddlesden-Popper series for a cathode material in IT-SOFC applications. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3598170] All rights reserved.