Oxygen isotopic exchange measurements of polycrystalline La 2 Ni 1−x Co x O 4+δ 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 La 2 NiO 4+δ . Of greater interest are the relatively high diffusion coefficients calculated for the high cobalt content materials, particularly the La 2 Ni 0.2 Co 0.8 O 4+δ and La 2 CoO 4+δ materials over the temperature range 450–650 °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 ∼470 °C.