La2-xMxNiO4+delta (M = Ba, Sr; x = 0.1, 0.3), with a formula of A(2)BO(4), has been prepared and investigated as cathode for solid oxide fuel cells to understand the influence of A-site dopants on the lattice structure, electrical conductivity and electrochemical properties of La2NiO4+delta. All the compositions belong to tetragonal I4/mmm space group. La2-xBaxNiO4+delta shows larger lattice parameters than La2-xSrxNiO4+delta due to the large ionic radius of Ba2+ compared with Sr2+. For both Ba and Sr, the parameters a and b decrease while the c increases with increasing doping level. Rietveld refinement demonstrates that the increase in c parameter is partially originated from the increase in rocksalt layer thickness (La-O2(x 1) bond), which makes the adsorbed oxygen on particle surface much easier to enter the lattice and form interstitials, and thereby promoting the electrode reaction. The electrical conductivity of La2-xMxNiO4+delta increases with doping level but decrease with increasing ionic radius of dopants. Both Ba and Sr doping decrease the electrode polarization and increase the power density of single-cell. La1.7Ba0.3NiO4+delta exhibits superior electrochemical properties than La1.7Sr0.3NiO4+delta. The La1.7Ba0.3NiO4+delta electrode exhibits the best performance with an ASR of 0.13 Omega cm(2) and a maximum power density of 310 mW cm(-2) at 800 degrees C under electrolyte (La0.8Sr0.2Ga0.83Mg0.17O3-delta, 300 mu m) - supported configuration. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.