A ceramic substrate for an electrochemical element that includes a ceramic layer and a high-thermal-expansion-coefficient material layer that is laminated on the surface of the ceramic layer. The high-thermal-expansion-coefficient material layer has a higher coefficient of thermal expansion than the ceramic layer, and applies compressive stress to the ceramic layer.

Described herein are redox flow batteries comprising a first aqueous electrolyte comprising a first type of redox active material and a second aqueous electrolyte comprising a second type of redox active material. The first type of redox active material may comprise one or more types of quinoxalines, or salts thereof. Methods for storing and releasing energy utilizing the described redox flow batteries are also provided.

A fuel cell is formed by laminating a plurality of cells. Each cell includes a membrane electrode assembly and two separators, which hold the membrane electrode assembly in between. Each separator includes a base member made of a metal material. A first layer is provided on the surface of the base member. The first layer includes a resin film and conductive particles that have greater hardness than the oxide film of the base member. Between the separators that are adjacent to each other, the first layers are in contact with each other.

An ion conductive intercalation membrane is useful to separate anode and cathode compartments in an electrochemical cell and provide ion transport between the anode and cathode compartments. The intercalation membrane does not receive and release electrons during operation of the electrochemical cell. An electric potential and current source is connected to an anode and a cathode disposed in respective anode and cathode compartments to cause oxidation and reduction reactions to occur at the anode and cathode, to cause electrons to flow through an external circuit coupled to the anode and cathode, and to cause ions to transport through the intercalation membrane to maintain charge neutrality within the electrochemical cell. The electrochemical cell operates at a current density greater than 25 mA/cm.sup.2 across the intercalation membrane.

An ion conductive intercalation membrane is useful to separate anode and cathode compartments in an electrochemical cell and provide ion transport between the anode and cathode compartments. The intercalation membrane does not receive and release electrons during operation of the electrochemical cell. An electric potential and current source is connected to an anode and a cathode disposed in respective anode and cathode compartments to cause oxidation and reduction reactions to occur at the anode and cathode, to cause electrons to flow through an external circuit coupled to the anode and cathode, and to cause ions to transport through the intercalation membrane to maintain charge neutrality within the electrochemical cell. The electrochemical cell operates at a current density greater than 25 mA/cm.sup.2 across the intercalation membrane.

A fuel cell component including a fuel cell substrate and a nitride material. The material may be a nitride compound having a chemical formula A.sub.xB.sub.yN.sub.z, where A is a metal, B is a metal different than A, N is nitrogen, x>0, y<7 and 0<z<12. The nitride compound may have a ratio of a stoichiometric factor to a reactivity factor of greater than 1.0. The stoichiometric factor indicates the reactivity of a nitride compound with chemical species as compared to a baseline nitride compound. The reactivity factor indicates the reaction enthalpy of the nitride compound and the chemical species as compared to a baseline nitride compound and the chemical species. The nitride compound may be Fe.sub.3Mo.sub.3N, Ni.sub.2Mo.sub.3N, Ni.sub.2W.sub.3N, CuNi.sub.3N, Fe.sub.3WN, Zn.sub.3Nb.sub.3N, V.sub.3Zn.sub.2N or a combination thereof. The nitride compound may be Si.sub.6Y.sub.3N.sub.11, Ni.sub.2Mo.sub.4N, Fe.sub.3Mo.sub.5N.sub.6 or a combination thereof.

A fuel cell according to the present disclosure includes separators 11 and 12 made of metal and having projection-depression shapes, and gas diffusion layers 13 and 14. Conductive particles 21 are buried in a projecting part on one surface of each of the separators 11 and 12, and carbon fibers 22 are buried in a projecting part on the other surface of each of the separators 11 and 12. The projecting parts on the one surfaces of the separators 11 and 12 abut against each other so that the conductive particles 21 buried in these projecting parts come into contact with each other. Further, the projecting parts on the other surfaces of the separators 11 and 12 abut against the gas diffusion layers 13 and 14, respectively, so that the carbon fibers 22 buried in these projecting parts come into contact with the gas diffusion layers 13 and 14, respectively.

A fuel cell according to the present disclosure includes separators 11 and 12 made of metal and having projection-depression shapes, and gas diffusion layers 13 and 14. Conductive particles 21 are buried in a projecting part on one surface of each of the separators 11 and 12, and carbon fibers 22 are buried in a projecting part on the other surface of each of the separators 11 and 12. The projecting parts on the one surfaces of the separators 11 and 12 abut against each other so that the conductive particles 21 buried in these projecting parts come into contact with each other. Further, the projecting parts on the other surfaces of the separators 11 and 12 abut against the gas diffusion layers 13 and 14, respectively, so that the carbon fibers 22 buried in these projecting parts come into contact with the gas diffusion layers 13 and 14, respectively.

Corrosion-resistant oxide films for use with proton exchange membrane fuel cells are described. Bipolar plates of proton exchange membrane fuel cells are subject to highly-acidic environments that can degrade the bulk material and associated properties of the bipolar plate leading to reduced proton exchange membrane fuel cell lifetimes. Materials, structures, and techniques for increasing the corrosion resistance of bipolar plates are disclosed. Such materials include substrates having a surface portion, which includes an Fe.sub.2O.sub.3 oxide layer having (110), (012), or (100) Fe.sub.2O.sub.3 surface facets configured to impart corrosion-resistance properties to the substrate.

Corrosion-resistant oxide films for use with proton exchange membrane fuel cells are described. Bipolar plates of proton exchange membrane fuel cells are subject to highly-acidic environments that can degrade the bulk material and associated properties of the bipolar plate leading to reduced proton exchange membrane fuel cell lifetimes. Materials, structures, and techniques for increasing the corrosion resistance of bipolar plates are disclosed. Such materials include substrates having a surface portion, which includes an Fe.sub.2O.sub.3 oxide layer having (110), (012), or (100) Fe.sub.2O.sub.3 surface facets configured to impart corrosion-resistance properties to the substrate.