Ni-NiO 30 wt% electrodes coated with LiMg0.05Co 0.95O2 cobaltite deposited on the substrate by complex sol-gel process were investigated using powder neutron diffraction. As the catalytic layer is only 1-2 microns thick, the diffracting volume of the cobaltite phase was increased by stacking 20 small rectangular pieces cut from the original electrode, assuming that the catalytic layer on the electrodes was homogenous. A pure bulk cobaltite sample was used as a reference for identifying the diffraction peaks of the catalytic layer in the complete electrode. Both an as-received sample and a tested electrode (100 h at 650 °C in a cell) were measured. Despite the small diffracting volume of the catalytic layer, due to the high flux available at D20, it was possible to detect the hexagonal phase and estimate its volume fraction in the as-received sample. In the tested electrode, the cobaltite material is no longer present, while traces of magnesium oxide and cobalt oxide are detected, suggesting significant modifications take place during use. © 2010 Materials Research Society.