Patent ID: 6893760

Claim:
A single cell, comprising: (a) a solid electrolyte layer; (b) an air electrode comprising: an adhering cathode layer formed on one surface of the solid electrolyte layer and configured to show a function to allow the air electrode and the solid electrolyte layer to adhere electrically and mechanically to each other, the adhering cathode layer comprising a conductive particle material having a particle diameter of 0.5 μm or less; and an electricity collecting cathode layer formed on the adhering cathode layer and configured to show an electricity collecting function of the air electrode, the electricity collecting cathode layer comprising a conductive particle having a particle diameter of 0.8 μm or more; and (c) a fuel electrode formed on the other surface of the solid electrolyte layer, wherein the adhering cathode layer is formed by using a PVD method and configures a three-phase interface composed of the solid electrolyte layer, reactive gas and the air electrode or a two-phase interface composed of the solid electrolyte layer and the air electrode, the electricity collecting cathode layer is formed by using one of a printing method and a spray coating method, is thicker than the adhering cathode layer, and has pores providing the reactive gas to the three-phase interface or the two-phase interface, a ratio (tc 1 /tc 2 ) of a thickness (tc 1 ) of the adhering cathode layer to a thickness (tc 2 ) of the electricity collecting cathode layer ranges from {fraction (1/1000)} to {fraction (1/500)}, and tc 1 and an average diameter (dc) of constituent particles of the air electrode satisfy a relation of 0.01 dc≦tc 1 ≦0.5 dc.