A double-layer anode structure on a pretreated porous metal substrate and a method for fabricating the same, for improving the redox stability and decreasing the anode polarization resistance of a SOFC. The anode structure includes: a porous metal substrate of high gas permeability; a first porous anode functional layer, formed on the porous metal substrate by a high-voltage high-enthalpy Ar—He—H.sub.2—N.sub.2 atmospheric-pressure plasma spraying process; and a second porous anode functional layer, formed on the first porous anode functional layer by a high-voltage high-enthalpy Ar—He—H.sub.2—N.sub.2 atmospheric-pressure plasma spraying and hydrogen reduction. The first porous anode functional layer is composed a redox stable perovskite, the second porous anode functional layer is composed of a nanostructured cermet. The first porous anode functional layer is also used to prevent the second porous anode functional layer from being diffused by the composition elements of the porous metal substrate.

According to various aspects of the present disclosure, a catalyst for rechargeable energy storage devices having a first transition metal and a second transition metal, wherein the first and second transition metals are formed on carbon nanotubes, the carbon nanotubes are doped with nitrogen and phosphorous, wherein the carbon nanotubes have edges and interlayer spaces and are axially aligned, and the first and second transition metals form bimetal centers, wherein the bimetal centers may be uniformly distributed catalytic active sites located at the edges or the interlayer spaces of the carbon nanotubes providing intercalated layers. The present FeCo—NPCNTs are a morphology-dependent catalyst that provides effective performance for bifunctional oxygen reduction reaction and oxygen evolution reaction in metal-air-cells and fuel cells.

An example of a stable electrode structure is to use a gradient electrode that employs large platinum particle catalyst in the close proximity to the membrane supported on conventional carbon and small platinum particles in the section of the electrode closer to a GDL supported on a stabilized carbon. Some electrode parameters that contribute to electrode performance stability and reduced change in ECA are platinum-to-carbon ratio, size of platinum particles in various parts of the electrode, use of other stable catalysts instead of large particle size platinum (alloy, etc), depth of each gradient sublayer. Another example of a stable electrode structure is to use a mixture of platinum particle sizes on a carbon support, such as using platinum particles that may be 6 nanometers and 3 nanometers. A conductive support is typically one or more of the carbon blacks.

A powder for an air electrode in a solid oxide fuel cell, the powder consisting of: a metal composite oxide having a perovskite-type single phase crystal structure represented by A1.sub.1-xA2.sub.xBO.sub.3-δ, where the element A1 is at least one selected from the group consisting of La and Sm, the element A2 is at least one selected from the group consisting of Ca, Sr, and Ba, the element B is at least one selected from the group consisting of Mn, Fe, Co, and Ni, 0<x<1, and the δ is an oxygen deficiency amount. When a cross section of a molded body obtained by compression molding the powder is observed at a magnification of 500 times, and a characteristic X-ray intensity of the element B is measured by an energy dispersive X-ray spectroscopy, the number of regions each having an intensity of 50% or higher of a maximum of the characteristic X-ray intensity of the element B and occupying 0.04% by area or more of the observation field of view is five or less.

A redox flow battery (“CRB”) performs as an energy storage system and has a negative electrode that directly utilizes CO.sub.2 in the battery charge step as an active species instead of metals. The CRB also has a positive electrode utilizing a metallic or non-metallic redox species, and a cation exchange membrane in between the negative and positive electrodes. The negative electrode comprises a porous base layer, a porous intermediate layer containing a metal oxide and a bi-functional catalyst layer for electrochemical reduction of CO.sub.2 or carbonate to formate and for formate oxidation to either carbonate or CO.sub.2. The bi-functional catalyst can be a PdSn based catalyst, such as PdSn, PdSnIn, and PdSnPb. The metal oxide in the intermediate layer acts as a catalyst support and can be a non-Platinum group metal (PGM) oxide, such as LaCoO.sub.3 or LaNiO.sub.3.

A solid oxide fuel cell (SOFC) assembly connectable to a source of a hydrocarbon fuel; said SOFC assembly comprises at least one SOFC. Each SOFC further comprises: (a) an anode support member having a nickel felt-made anode current collector; (b) an electrolyte layer disposed on the anode support member; and a cathode having a cathode current collector; the cathode disposed on said electrolyte layer. The nickel felt-made anode current collector is doped with Scandium.

A system and method of continuous fabrication of multi-material graded structures using additive manufacturing is disclosed. Using multi-material feedstocks and optimized processing parameters, the gradient on composition and structure are controlled to achieve smooth transition from one functional component to another functional component. A multi-material graded structure is produced as the feedstocks are transported from the feedstock reservoir system comprised of many different materials. Interface transition from one functional layer to the next is gradient, controlled by feedstock mixture ratios based on the flow rate control for the feedstock system. Composition includes chemical composition, physical composition, and porosity. Continuous automatic additive manufacturing method makes the fabrication more efficient and avoids joining problems. This method finds application in fabrication of a fuel cell, battery, reformer and other chemical reaction and process units, including structures made of multiple units, such as stacks, that incorporate multiple functional components.

An atomically dispersed precursor (ADP) for preparing a non-platinum group metal electrocatalyst includes: sacrificial metal centers comprising a sacrificial metal selected from Cd and Zn; metal active sites comprising a transition metal; and first and second ligands linking the sacrificial metal centers and the metal active sites into a network. The ADP may be immobilized on a carbon support. The first and second ligands may comprise N-containing ligands of different carbon chain lengths. Alternatively, the first and second ligands may comprise N-containing ligands and O-containing ligands, respectively.

Improved catalyst layers for use in fuel cell membrane electrode assemblies, and methods for making such catalyst layers, are provided. Catalyst layers can comprise structured units of catalyst, catalyst support, and ionomer. The structured units can provide for more efficient electrical energy production and/or increased lifespan of fuel cells utilizing such membrane electrode assemblies. Catalyst layers can be directly deposited on exchange membranes, such as proton exchange membranes.

Disclosed is a method for infiltrating a porous structure with a precursor solution by means of humidification. The infiltration method with a precursor solution using moisture control comprises the steps of: (S1) providing a substrate having porous structures deposited thereon; (S2) depositing, by electrospraying, a precursor solution on the substrate having porous structures deposited thereon; (S3) humidifying the porous structures having the precursor solution deposited thereon; and (S4) sintering the humidified porous structures.