In some examples, a fuel cell including a first electrochemical cell; a second electrochemical cell; an interconnect configured to conduct a flow of electrons from the first electrochemical cell to the second electrochemical cell; and a dense oxygen barrier layer separating the interconnect from one of a cathode or a cathode conductor layer adjacent the cathode, wherein the dense barrier layer is formed of a ceramic material exhibiting a low porosity and a high conductivity such that the dense oxygen barrier layer reduces at least one precious metal loss from the interconnect or oxidation of nickel metal in the interconnect.

An electrode can include a functional layer having an Ln.sub.2MO.sub.4 phase, where Ln is at least one lanthanide optionally doped with a metal and M is at least one 3d transition metal, and a heavily-doped ceria phase. An electrochemical device or a sensor device can include the electrode.

In accordance with the present disclosure, a method for fabricating a symmetrical solid oxide fuel cell is described. The method includes synthesizing a composition comprising perovskite and applying the composition on an electrolyte support to form both an anode and a cathode.

The invention provides a matrix material for the gas diffusion layer of the polymer electrolyte membrane fuel cell, which is composed of three-dimensional porous and strip-shaped hexagonal chambers connected to each other, wherein the six-sided ribs are composed of two metal layers, the inside is metal nickel, and the outside is tungsten-nickel alloy. The total mass of metal per square meter of the material is: 1500˜3000 grams, the mass content of metal nickel in the material is 88˜92%, the mass content of metal tungsten is 8˜12%, and the rest are impurities; the thickness of the matrix material is 0.1˜0.2 mm, specific surface area is (1˜2)×10.sup.5 m.sup.2/m.sup.3; longitudinal air permeability ≥2000 m/mm/(cm.sup.2hmmAq), longitudinal thermal conductivity ≥1.7W/(m.Math.k), transverse thermal conductivity ≥21W/(m.Math.K). The porous nickel-tungsten metal material of the invention, as the matrix material of the gas diffusion layer, has the advantages of lower electrical resistance and higher strength compared with carbon paper.

The present invention relates to a method for preparing an electrode-supported electrochemical half-cell including a step consisting in subjecting a green electrode layer on which a precursor gel of the electrolyte or a precursor thereof is deposited to sintering at a temperature of less than or equal to 1350° C.

This invention relates to a method for preparing an air electrode based on Pr.sub.2-xNiO.sub.4 with 0≦x<2, comprising a step consisting in sintering a ceramic ink comprising Pr.sub.2-xNiO.sub.4 and a pore-forming agent at a temperature above 1000° C. and below or equal to 1150° C. This invention also relates to the air electrode thus obtained and its uses.

A membrane electrode assembly of an electrochemical device includes a proton conductive solid electrolyte membrane and an electrode including Ni and an electrolyte material which contains as a primary component, at least one of a first compound having a composition represented by BaZr.sub.1-x1M.sup.1.sub.x1O.sub.3 (M.sup.1 represents at least one element selected from trivalent elements each having an ion radius of more than 0.720 A° to less than 0.880 A°, and 0<x.sub.1<1 holds) and a second compound having a composition represented by BaZr.sub.1-x2Tm.sub.x2O.sub.3 (0<x.sub.2<0.3 holds).

A membrane electrode assembly includes an electrode consisting of lanthanum strontium cobalt complex oxide or consisting of a composite of lanthanum strontium cobalt complex oxide and an electrolyte material, and a first solid electrolyte membrane represented by a composition formula of BaZr.sub.1-xYb.sub.xO.sub.3-δ (0<x<1). The electrode is in contact with the first solid electrolyte membrane.

A cell stack device includes a cell stack, a holding member, and a positive electrode terminal. The cell stack is constructed by stacking a plurality of cells. The holding member holds the cells. The positive electrode terminal functions as a positive electrode when power generated by the cell stack is output to the outside. The potential of the positive electrode terminal is not more than that of the holding member.

Electrochemical device using thin micro-porous metal sheets. The porous metal sheet may have a thickness less than 200 μm, provides three-dimensional networked pore structures of pore sizes in the range of 2.0 nm to 5.0 μm, and is electrically conductive. The micro-porous metal sheet is used for positively and/or negatively-charged electrodes by providing large specific contact surface area of reactants/electron. Nano-sized catalyst or features can be added inside pores of the porous metal sheet of pore sizes at sub- and micrometer scale to enhance the reaction activity and capacity. Micro-porous ceramic materials may be coated on the porous metal sheet at a thickness of less than 40 μm to enhance the functionality of the porous metal sheet and may function as a membrane separator. The electrochemical device may be used for decomposing molecules and for synthesis of molecules such as synthesis of ammonia from water and nitrogen molecules.