Performance of La0.9Sr0.1Ga0.5Ni0.5O3 as a Cathode for a Lanthanum Gallate Fuel 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 interruption technique. The electrode performance was found to be clearly superior to La0.85Sr0.15MnO3 and comparable to La0.6Sr0.4CoO3 in the temperature range of 700–850°C. The exchange current density is a maximum in air and is smaller in either 100% O2 or 2% O2 suggesting that the occupation of surface adsorption sites is important. The overpotential-current density 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.