Abstract: An electrochemical reaction single cell including an electrolyte layer containing Zr and at least one of Y, Sc, and Ca, an anode disposed on one side of the electrolyte layer, a cathode containing Sr and Co and disposed on the other side of the electrolyte layer, and an intermediate layer disposed between the electrolyte layer and the cathode. The electrochemical reaction single cell exhibits an interface contact ratio of 25.5% to 68.6%, wherein the interface contact ratio is the ratio of the sum of the lengths of portions containing neither SrZrO3 nor cavities of an interfacial surface of the intermediate layer on the electrolyte layer side to the total length of the interfacial surface. Also disclosed is an electrochemical reaction cell stack including a plurality of electrochemical reaction single cells, at least one of which is the above described electrochemical reaction single cell.

Abstract: An electrochemical reaction single cell including an electrolyte layer containing Zr and at least one of Y, Sc, and Ca, an anode disposed on one side of the electrolyte layer, a cathode containing Sr and Co and disposed on the other side of the electrolyte layer, and an intermediate layer disposed between the electrolyte layer and the cathode. The electrochemical reaction single cell exhibits an interface contact ratio of 25.5% to 68.6%, wherein the interface contact ratio is the ratio of the sum of the lengths of portions containing neither SrZrO3 nor cavities of an interfacial surface of the intermediate layer on the electrolyte layer side to the total length of the interfacial surface. Also disclosed is an electrochemical reaction cell stack including a plurality of electrochemical reaction single cells, at least one of which is the above described electrochemical reaction single cell.

Abstract: A solid oxide fuel cell, a method of producing the same, a fuel cell stack, and a solid oxide fuel battery. The fuel cell including a solid electrolyte layer, a cathode layer formed on one surface thereof and which contains at least Sr, an anode layer which is formed on the other surface of the solid electrolyte layer, and an intermediate layer formed between the solid electrolyte layer and the cathode layer. At least a part of the intermediate layer is an element diffusion prevention layer; the element diffusion prevention layer being formed of a complex oxide containing at least one rare earth element and Zr; and after having been subjected to accelerated heating in air at 1,000° C. for 100 hr, the element diffusion prevention layer has a thickness of 600 nm or more to 2,000 nm or less and a percent Sr coverage of 90% or lower.