Reduction studies and evaluation of surface modified A-site deficient La-doped SrTiO3 as anode material for IT-SOFCs

Here we report a study of the properties of A-site deficient lanthanum-doped SrTiO3(La0.2Sr0.7TiO3) in order to establish its potential as an anode component material for intermediate temperature SOFCs. The behaviour of the material in reducing atmosphere has been investigated and results of thermal expansion and conductivity dependence of the oxygen partial pressures are presented revealing a strong dependence of the material's thermal and electrical properties on temperature and atmosphere. From thermogravimetry, dilatometry and conductivity measurements it seems that reduction may become more facile as the extent of reduction increases. Two types of fuel cells, electrolyte supported and electrode supported, were produced using yttria-stabilized zirconia (YSZ) electrolyte, a porous, conductive backbone of La0.2Sr0.7TiO3 impregnated via solutions with catalytically active 20 mol% gadolinia-doped ceria and copper, for improved current collection as anode, and thin films of La0.6Sr0.4CoO3 produced in situ in the fuel cell test experiment as cathode. Fuel cell tests using pure, humidified H-2 as fuel demonstrated that power densities in excess of 0.5 W cm(-2) at 750 degrees C can be achieved using these cells with suitable pre-reduction of the titanate material.