Research Process on Determination of Oxygen Surface Exchange Coefficient for Oxygen Electrode Materials of Reversible Solid Oxide Cells

Energy storage and fuel cell power generation are the most important development directions for realizing the carbon neutrality goal in China. Reversible solid oxide cells (i.e., RSOCs) are promising electrochemical energy conversion devices with a high efficiency and a low emission. The polarization resistance of oxygen electrode is large, and oxygen reduction/evolution reaction (ORR/OER) is sluggish. A lower oxygen exchange rate is considered as a main rate limiting step in reactions of RSOCs, restricting the efficiency and performance. This review summarized various techniques for characterizing the oxygen surface exchange coefficient (k), and introduced the working principle, merits and research progress of optical transmission relaxation approach. Also, this review discussed the factors like defect chemistry, surface chemistry, orientation, grain boundary/grain size and the crystallinity on the oxygen exchange kinetics and catalytic activity of oxygen electrode, and gave some advices for the future research.