In single-chamber solid oxide fuel cells (SC-SOFC), anode and cathode are placed in a gas chamber where they are exposed to a fuel/air mixture. Similarly to conventional dual-chamber SOFC, the anode and the cathode are separated by an electrolyte. However, as in the SC-SOFC configuration the electrolyte does not play tightness role between compartments, this one can be a porous layer. Nevertheless, it is necessary to have a diffusion barrier to prevent the transportation of hydrogen produced locally at the anode to the cathode that reduces fuel cell performances. This study aims to obtain directly a diffusion barrier through the surface densification of the electrolyte Ce 0.9 Gd 0.1 O 1.95 (CGO) by a laser treatment. KrF excimer laser and Yb fiber laser irradiations were used at different fluences and number of pulses to modify the density of the electrolyte coating. Microstructural characterizations confirmed the modifications on the surface of the electrolyte for appropriate experimental conditions showing either grain growth or densified but cracked surfaces. Gas permeation and electrical conductivities of the modified electrolyte were evaluated. Finally SC-SOFC performances were improved for the cells presenting grain growth at the electrolyte surface.
Laser induced densification of ceramic oxide has shown great promises. However to control this process in regards of the final properties of the material, it is necessary to understand phenomena occurring during laser matter interaction, especially heat diffusion through the material. A thermal simulation of cerium gadolinium oxide (CGO) submitted to infrared laser pulses is presented. In order to determine the temperature profile during laser treatment, optical properties of CGO must be known; for this purpose, ellipsometry measurements were performed in order to obtain absorption coefficient and reflectivity. Finally, a thermal model based on heat equation was developed. Experimental observations of irradiated CGO surfaces were in agreement with the simulation results, in particular at maximum temperature when the material reaches fusion.
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