Oxygen isotopic exchange measurements of polycrystalline La2Ni1-xCoxO4+delta have been carried out for the 30%, 50%, 80% and 100% Co doped materials and both the oxygen tracer diffusion coefficient, D*, and surface exchange coefficient, k, determined. Each of the high Co content materials (x >= 0.5) was found to have higher diffusion and surface exchange coefficients than the previously reported parent compound La2NiO4+delta. Of greater interest are the relatively high diffusion coefficients calculated for the high cobalt content materials, particularly the La2Ni0.2Co0.8O4+delta and La2CoO4+delta materials over the temperature range 450-650 degrees C. As the surface exchange coefficients for these materials are also high these materials then meet the D*k product requirement of 10(-14) cm(3) s(-2) for cathodes at the low temperature of similar to 470 degrees C. (c) 2005 Elsevier B.V. All rights reserved.