Nanoporous 1-mu m thin La0.6Sr0.4CoO3-delta (LSC) layers are deposited by spray pyrolysis and subsequently sintered at 600 degrees C, 800 degrees C, and 1000 degrees C. A strontium- and oxygen-rich phase can be found within the pore network, which appears at low sintering temperatures. This so-called "secondary phase" occupies up to 20.7 vol.% of the LSC films for the 600 degrees C annealing process. It does not hinder the electrochemical activity towards oxygen reduction of such layers that exhibit an area-specific resistance (ASR) as low as 0.13 Omega cm(2) at 600 degrees C in air. This result makes the spray pyrolysed LSC thin films promising candidates as intermediate-temperature solid oxide fuel cell cathodes. For higher sintering temperatures the secondary phase progressively disappears. A correlation between the inverse of the ASR and the whole LSC surface area (regardless of the presence of the secondary phase or not) is also evidenced. The increase of ASR with increasing sintering temperature is found to be primarily related to the exchange neutral flux density of the Sr-deficient LSC. (C) 2014 Elsevier B.V. All rights reserved.