The use of a dual-composite approach, in which both LSM and YSZ nanoparticles are placed on YSZ core particles, allows for the development of an ideal cathode microstructure with improved phase contiguity and durability for use in solid oxide fuel cells. The volume fraction of the conjugated YSZ phase plays a critical role in the optimization of the cathode microstructure for achieving good durability because it acts as an interconnecting bridge between YSZ core particles. However, the presence of excess conjugated YSZ phase interrupts the formation of sufficient triple phase boundary sites by disturbing the contacts between the LSM and YSZ phases. Impedance spectroscopy analysis and microstructural observations provide a better understanding of the influence of the composition on the electrochemical performance and durability of these dual composite cathodes. (c) 2008 Elsevier B.V. All rights reserved.