Performance of La0.9Sr0.1Ga0.5Ni0.5O3 as a cathode for a lanthanum gallatefuel cell

The cathodic overpotential of a La0.9Sr0.1Ga0.5Ni0.5O3 (LSGN) electrode on a La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolyte was studied using the current i nterruption technique. The electrode performance was found to be clearly su perior to La0.85Sr0.15MnO3 and comparable to La0.6Sr0.4CoO3 in the temperat ure range of 700-850 degreesC. The exchange current density is a maximum in air and is smaller in either 100% O-2 or 2% O-2 suggesting that the occupa tion of surface adsorption sites is important. The overpotential-current de nsity curves suggest that charge transfer is the limiting process for high current densities. An energy dispersive spectrometry line scan did not show any significant interdiffusion of Ni ions across the electrode/electrolyte boundary.