Specific considerations for obtaining appropriate La_1-xSr_xGa_1-yMg_yO_3-δ thin films using pulsed-laser deposition and its influence on the performance of solid-oxide fuel cells

To obtain La_1-xSr_xGa_1-yMg_yO_3-δ (LSGM) thin films with the appropriate properties, pulsed-laser deposition (PLD) is employed, and specific considerations regarding control of the deposition parameters is investigated. It is demonstrated that with a target of stoichiometric composition, appropriate LSGM thin films cannot be produced because of the deviation of the composition from the target to the thin film. Only after adjusting the target composition an LSGM thin film with an appropriate composition and phase can be obtained. The optimized LSGM thin film possesses an electrical conductivity close to that of the bulk LSGM. In contrast, non-optimized thin films do not yield any measurable electrical conductivity. The impact of the optimization of the LSGM thin-film electrolyte on the cell performance is quite significant, in that a solid-oxide fuel cell (SOFC) with an optimized LSGM thin-film electrolyte produces a maximum power density of 1.1 W cm^-2 at 600 °C, whereas an SOFC with a non-optimal LSGM thin-film electrolyte is not operable.