Chemical and structural changes in manganese-doped yttria-stabilized zirconia studied by electron energy loss spectroscopy combined with electron diffraction

Solid solution of manganese in yttria-stabilized zirconia (YSZ) may occur in the electrolyte of solid oxide fuel cells. Possible changes in valence, coordination, and site occupancy of Mn in YSZ are of interest. Also, subsequent structural modification of the cubic YSZ, as well as the possible ordering of vacancies, has important consequences for the ionic conductivity, Electron energy loss spectroscopy was used to measure the O K and the Mn L edge of Mn in solid solution in a zirconia host lattice. The ratio Mn L-3/L-2 was determined for some manganese oxides and for Mn in solid solution. It is shown that the L-3/L-2, ratio does not simply reflect the oxidation state of the Mn ions in solid solution, Selected area diffraction experiments were also made in the TEM, This showed ordering of the cations and the anion vacancies at high doping levels, It is concluded that the number of O ions surrounding each Mn ion may be very important in interpreting the obtained L-3/L-2 ratio.