A method for operating a solid oxide electrolysis cell which can suppress degradation of the hydrogen electrode, is provided. A method for operating a solid oxide electrolysis cell includes a hydrogen electrode, an oxygen electrode, and an electrolyte layer sandwiched between the hydrogen electrode and the oxygen electrode. The hydrogen electrode includes a catalyst layer structured with Ni-containing particles dispersed and supported on a porous mixed ionic and electronic conducting oxide. The method includes an alternating operation in which a water vapor electrolysis operation and a fuel cell operation are repeated alternately.

Disclosed is a method of manufacturing a solid oxide fuel cell including a multi-layered electrolyte layer using a calendering process. The method for manufacturing a solid oxide fuel cell is a continuous process, thus providing high productivity and maximizing facility investment and processing costs. In addition, the solid oxide fuel cell manufactured by the method includes an anode that is free of interfacial defects and has a uniform packing structure, thereby advantageously greatly improving the production yield and power density. In addition, the solid oxide fuel cell has excellent interfacial bonding strength between respective layers included therein, and includes a multi-layered electrolyte layer in which the secondary phase at the interface is suppressed and which has increased density, thereby advantageously providing excellent output characteristics and long-term stability even at an intermediate operating temperature.

A method of manufacturing a solid oxide fuel cell stack, including alternately disposing a plurality of single fuel cells, and a plurality of interconnectors disposed alternately and holding the alternately disposed plurality of single fuel cells and plurality of interconnectors between a pair of end members, forming a space between a first end member and a first interconnector, disposing a junction member composed of an elastic member and an electrically conductive member in the space, and urging a portion of an electrically conductive member and another portion of the electrically member against the first end member and the first interconnector so that a total thickness of the portion of the electrically conductive member, the another portion of the electrically conductive member, and the elastic member prior to being disposed in the space between the first end member and the first interconnector is greater than a height of the space.

A method of manufacturing a solid oxide fuel cell stack, including alternately disposing a plurality of single fuel cells, and a plurality of interconnectors disposed alternately and holding the alternately disposed plurality of single fuel cells and plurality of interconnectors between a pair of end members, forming a space between a first end member and a first interconnector, disposing a junction member composed of an elastic member and an electrically conductive member in the space, and urging a portion of an electrically conductive member and another portion of the electrically member against the first end member and the first interconnector so that a total thickness of the portion of the electrically conductive member, the another portion of the electrically conductive member, and the elastic member prior to being disposed in the space between the first end member and the first interconnector is greater than a height of the space.

Provided is a proton conductor that achieves an improvement in transport number while suppressing a decrease in conductivity. The proton conductor contains a metal oxide having a perovskite structure and represented by formula (1): A.sub.aB.sub.1-x-yB′.sub.xM.sub.yO.sub.3-δ (1), wherein an element A is at least one element selected from the group consisting of Ba, Sr, and Ca, an element B is at least one element selected from the group consisting of Zr and Ce, an element B′ is Hf, an element M is at least one element selected from the group consisting of Y, Yb, Er, Ho, Tm, Gd, In, and Sc, δ is an oxygen deficiency amount, and “a”, “x”, and “y” satisfy 0.9≤a≤1.0, 0.1≤y≤0.2, and 0<x(1−y)≤0.2.

Provided is a proton conductor that achieves an improvement in transport number while suppressing a decrease in conductivity. The proton conductor contains a metal oxide having a perovskite structure and represented by formula (1): A.sub.aB.sub.1-x-yB′.sub.xM.sub.yO.sub.3-δ (1), wherein an element A is at least one element selected from the group consisting of Ba, Sr, and Ca, an element B is at least one element selected from the group consisting of Zr and Ce, an element B′ is Hf, an element M is at least one element selected from the group consisting of Y, Yb, Er, Ho, Tm, Gd, In, and Sc, δ is an oxygen deficiency amount, and “a”, “x”, and “y” satisfy 0.9≤a≤1.0, 0.1≤y≤0.2, and 0<x(1−y)≤0.2.

A fuel cell includes: an electrolyte layer; a base electrode formed on one side of the electrolyte layer; and a catalyst electrode formed on the other side of the electrolyte layer to be apart from the base electrode with the electrolyte layer interposed therebetween. The catalyst electrode includes: a first electrode portion that covers a part of the electrolyte layer; and a second electrode portion that covers a part of a surface of the first electrode portion to form an electrode portion interface in contact with the first electrode portion.

A solid oxide fuel cell comprising an anode, an electrolyte, and a cathode comprising Pr.sub.xCo.sub.yO.sub.3, wherein the ratio of x and y are 1:1.

A solid oxide fuel cell comprising an anode, an electrolyte, and a cathode comprising Pr.sub.xCo.sub.yO.sub.3, wherein the ratio of x and y are 1:1.

A solid oxide fuel cell including a hydrocarbon reforming catalyst and a method for forming the solid oxide fuel cell are provided. An exemplary solid oxide fuel cell includes a cell. The cell includes a filled metal substrate including holes substantially filled with a permeable material that includes a hydrocarbon reforming catalyst, wherein the filled metal substrate has a front facing a fuel flow and a back facing an electrochemical stack. A permeable layer is formed on the back of the filled metal substrate that is in contact with the permeable material of the filled holes. The cell includes an anode layer proximate to the permeable layer, an electrolyte layer proximate to the anode layer, a diffusion barrier proximate to the anode layer, and a cathode proximate to the diffusion barrier.