US Patent 11189842 Electrochemical cell

An electrochemical cell includes a fuel electrode, an air electrode containing a perovskite type oxide as a main component, the perovskite type oxide being represented by a general formula ABO3 and containing La and Sr at the A site, and a solid electrolyte layer arranged between the fuel electrode and the air electrode. The air electrode includes a first portion and a second portion, the first portion being located on the most upstream side in a flow direction of an oxidant gas that flows through a surface of the air electrode, the second portion being located on the most downstream side in the flow direction. A first ratio of a La concentration to a Sr concentration detected at the first portion through Auger electron spectroscopy is at least 1.1 times a second ratio of a La concentration to a Sr concentration detected at the second portion through Auger electron spectroscopy.