Redox flow devices are described including a positive electrode current collector, a negative electrode current collector, and an ion-permeable membrane separating said positive and negative current collectors, positioned and arranged to define a positive electroactive zone and a negative electroactive zone; wherein at least one of said positive and negative electroactive zone comprises a flowable semi-solid composition comprising ion storage compound particles capable of taking up or releasing said ions during operation of the cell, and wherein the ion storage compound particles have a polydisperse size distribution in which the finest particles present in at least 5 vol % of the total volume, is at least a factor of 5 smaller than the largest particles present in at least 5 vol % of the total volume.

Redox flow devices are described including a positive electrode current collector, a negative electrode current collector, and an ion-permeable membrane separating said positive and negative current collectors, positioned and arranged to define a positive electroactive zone and a negative electroactive zone; wherein at least one of said positive and negative electroactive zone comprises a flowable semi-solid composition comprising ion storage compound particles capable of taking up or releasing said ions during operation of the cell, and wherein the ion storage compound particles have a polydisperse size distribution in which the finest particles present in at least 5 vol % of the total volume, is at least a factor of 5 smaller than the largest particles present in at least 5 vol % of the total volume.

Improved contact between interconnect and oxygen electrode material in solid oxide cell (SOC) stacks is achieved through a contact point between the oxygen electrode or an oxygen-side contact layer of the SOC and a coated ferritic stainless steel interconnect in the SOC stack, where the coating on the metallic interconnect comprises Cu.

Improved contact between interconnect and oxygen electrode material in solid oxide cell (SOC) stacks is achieved through a contact point between the oxygen electrode or an oxygen-side contact layer of the SOC and a coated ferritic stainless steel interconnect in the SOC stack, where the coating on the metallic interconnect comprises Cu.

A bipolar plate includes a substrate and a coating film that is formed at least on a part of a surface of the substrate. The coating film includes a phosphide having a composition represented by M.sub.2-xTi.sub.xP, where M is any one or more elements selected from the group consisting of Ni, Co, Fe, Mn and Cr, and 0.1x1.9. The coating film preferably includes two kinds or more of the metal elements M, and preferably has a thickness ranging from 0.05 m or greater to 100 m or less.

A surface treatment method of a fuel cell separator capable of suppressing temperature unevenness of the fuel cell separator is provided. In the surface treatment method, an antimony-doped tin oxide (ATO) film is formed on a surface of a fuel cell separator (W1) used for a fuel cell. The fuel cell separator (W1) is heated using a high-frequency induction heating method (S1). By spraying solution (L1) including antimony and tin onto the fuel cell separator (W1), the ATO film is caused to be formed on the surface of the fuel cell separator (W1) (S2).

A fuel cell manufacturing method capable of easily forming an interconnector part electrically connecting adjacent unit cells in a planar array fuel cell is provided. The interconnector part (30) is formed through a local heating process of carbonizing a proton conductive resin by locally heating an electrolyte membrane (12). The local heating process includes: a first heating step of heating a part of the electrolyte membrane (12) to a temperature equal to or less than a first temperature at a first temperature increase rate or less; and a second heating step of heating the part of the electrolyte membrane (12) to a temperature equal to or greater than a second temperature higher than the first temperature at a temperature increase rate greater than the first temperature increase rate, after the first heating step.

Fuel cell alloy bipolar plates. The alloys may be used as a coating or bulk material. The alloys and metallic glasses may be particularly suitable for proton-exchange membrane fuel cells because of they may exhibit reduced weights and/or better corrosion resistance. The alloys may include any of the following Al.sub.xCu.sub.yTi.sub.z, Al.sub.xFe.sub.yNi.sub.z, Al.sub.xMn.sub.yNi.sub.z, Al.sub.xNi.sub.yTi.sub.z, Cu.sub.xFe.sub.yTi.sub.z, Cu.sub.xNi.sub.yTi.sub.z, Al.sub.xFe.sub.ySi.sub.z, Al.sub.xMn.sub.ySi.sub.z, Al.sub.xNi.sub.ySi.sub.z, Ni.sub.xSi.sub.yTi.sub.z, and C.sub.xFe.sub.ySi.sub.z. The alloys or metallic glass may be doped with various dopants to improve glass forming ability, mechanical strength, ductility, electrical or thermal conductivities, hydrophobicity, and/or corrosion resistance.

Fuel cell alloy bipolar plates. The alloys may be used as a coating or bulk material. The alloys and metallic glasses may be particularly suitable for proton-exchange membrane fuel cells because of they may exhibit reduced weights and/or better corrosion resistance. The alloys may include any of the following Al.sub.xCu.sub.yTi.sub.z, Al.sub.xFe.sub.yNi.sub.z, Al.sub.xMn.sub.yNi.sub.z, Al.sub.xNi.sub.yTi.sub.z, Cu.sub.xFe.sub.yTi.sub.z, Cu.sub.xNi.sub.yTi.sub.z, Al.sub.xFe.sub.ySi.sub.z, Al.sub.xMn.sub.ySi.sub.z, Al.sub.xNi.sub.ySi.sub.z, Ni.sub.xSi.sub.yTi.sub.z, and C.sub.xFe.sub.ySi.sub.z. The alloys or metallic glass may be doped with various dopants to improve glass forming ability, mechanical strength, ductility, electrical or thermal conductivities, hydrophobicity, and/or corrosion resistance.

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.