Neutron diffraction study of lithium cobaltites for molten carbonate fuel cells

Three different cobaltites, of interest for fuel cell technology, stoichiom etric LiCuO2, Li1.08CoO2 and Mg-doped LiCoO2, have been investigated using neutron powder diffraction. The measurements were carried oat both at room temperature and at 650 degrees C. The analysis of the diffraction data by m eans of Rietveld refinement (space group R-3 m) shows that, at the two inve stigated temperatures, increasing the Li content increases lattice paramete r cc, while both a and c increase when Mg is added. Furthermore, for the Mg -doped powder, Mg partly replaces Co in octahedral (3b) site and partly rem ains as MgO. (C) 2000 Elsevier Science B.V. All rights reserved.