Oxygen diffusion and surface exchange in La2-xSrxNiO4+delta

The compounds La2-xSrxNiO4+delta, x = 0, 0.1, have been prepared with an ox ygen excess of up to delta = 0.24. The oxygen tracer diffusion coefficient Md surface exchange coefficient of the materials have been determined by th e isotope exchange depth profile method (IEDP). La2NiO4+delta was found to have an oxygen diffusivity higher than that of La0.6Sr0.4Co0.2Fe0.8O3 (LSCF ) and one order of magnitude lower than the best perovskite oxide ion condu ctor La0.3Sr0.7CoO3 (LSC). The fast oxide ion diffusion of La2NiO4+delta co mbined with its thermal stability indicate that this material would be a go od candidate for use in ceramic oxygen generators (COGs) and solid oxide fu el cells (SOFCs). Furthermore, optimisation by a combination of donor and/o r acceptor doping should improve the properties reported here. (C) 2000 Els evier Science B.V. All rights reserved.