Feasibility study for the application of operando UV-Vis reflectance spectroscopy for Nickel agglomeration and sulfur posioning of Ni/YSZ fuel cell electrodes

Recent advances in spectro-electrochemical measurement apparatus have allowed for operando investigation of ceramics under variable gaseous environments. Specifically, this system has enabled high temperature studies under varying degrees of reducing hydrogen flow. Broadly applicable, this set-up has allowed for the investigation of operation and degradation mechanisms in solid oxide fuel cell electrodes, among other gas sensor studies. In fuel cells, Ni/YSZ cermet electrodes are often used to facilitate the electrochemical conversion of hydrogen and oxygen to form water and generate electrical energy, or the reverse in electrolyzer mode. Nickel agglomeration within fuel cell/electrolyzer electrodes is a primary degradation mechanism during operation. Additionally, sulfur contaminants from fuel sources poison these electrochemically active cermets. Since Nickel and sulfur both exhibit characteristic UV-Vis absorption features, a feasibility study will be carried out to verify the applicability of operando UV-Vis reflectance spectroscopy to monitor the growth of nickel particles in cermet electrodes and the sulfur poisoning of these functional materials. Using these direct measurements, comparison to literature and proposed models serves as an attractive avenue for future study.