Study of a novel microstructured air electrode/electrolyte interface for solid oxide cells

Solid Oxide Cells (SOCs) are promising high temperature electrochemical devices to obtain clean energies from renewable sources. Their high operating temperatures (800-1000 degrees C) contribute to the degradation of the cell components. Intermediate Temperature SOCs (IT-SOCs) appear as an alternative to decrease the operating temperatures (600-800 degrees C) and avoid cell degradation, nevertheless, the electrochemical performance is affected by energy dissipation, principally by the air electrode overpotentials. This work presents the surface modification of Ce0.80Sm0.20O2-delta (SDC) electrolyte by Femtosecond Laser Micromachining (FLM) to increase the surface/area ratio and therefore improve the electrochemical performance. A pattern with an equally spaced pillar shape microstructure was obtained and characterized. (La0.60Sr0.40)(0.95)Co0.20Fe0.80O3-delta (LSCF) powder was used as porous air electrode to determine the electrochemical benefits of the pattern. Polarization resistance (R-p) of air electrode in patterned sample was about five times lower than in flat one at 600 degrees C and after 45 h, which suggested an improvement in the electrical and chemical features over time. These enhancements could be explained by the synergistic effect among surface/area ratio, nano-microcrystalline domains and superficial Ce3+ concentration in the patterned electrolyte. R-p values are higher than those reported for best air electrodes, however, FLM has proven its benefits in electrochemical performance.