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 oC) contribute to the degradation of the cell components. Intermediate Temperature SOCs (IT-SOCs) appear as an alternative to decrease the operating temperatures (600-800 oC) 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-? (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)0.95Co0.20Fe0.80O3-? (LSCF) powder was used as porous air electrode to determine the electrochemical benefits of the pattern. Polarization resistance (Rp) of air electrode in patterned sample was about five times lower than in flat one at 600 oC 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. Rp values are higher than those reported for best air electrodes, however, FLM has proven its benefits in electrochemical performance.