A comparison of the transport properties of La2−xSrxNi1−yFeyO4+δ where 0

Recently there has been substantial interest in optimising perovskite type ceramics as mixed ionic-electronic conductors (MIECs) for use in ceramic oxygen generators and solid oxide fuel cells. However these materials suffer from thermomechanical deficiencies and therefore there is a need to develop alternative materials. Using the IEDP/SIMS technique the La_2−xSr_xNi_1−yFe_yO_4+δ series of compounds has been investigated and the oxygen tracer diffusion and surface exchange coefficients determined. It has been found that the oxide ion diffusivity of the x and y=0 material is very close to that of the fast oxide ion conducting perovskites such as La_1−xSr_xCoO₃ (LSC) but on acceptor doping with Sr a considerable decrease in the oxygen tracer diffusion coefficient was observed. Further studies on the effects of B site doping, where y>0, indicate that this has very little effect on the transport properties. Paper presented at the 6th Euroconference on Solid State Ionics, Cetraro, Calabria, Italy, Sept. 12–19, 1999.