A fuel cell power generation system is provided with: at least one fuel cell module each of which includes a fuel cell having a fuel-side electrode, an electrolyte, and an oxygen-side electrode; at least one fuel supply line for supplying a fuel gas to the fuel-side electrode included in the at least one fuel cell module; at least one oxidizing gas supply line for supplying an oxidizing gas to the oxygen-side electrode included in the at least one fuel cell module; and a most downstream exhaust fuel gas line through which an exhaust fuel gas discharged from a most downstream module that is disposed most downstream in a flow of the fuel gas among the at least one fuel cell module flows. The most downstream exhaust fuel gas line is configured to supply the exhaust fuel gas to the oxygen-side electrode included in any of the fuel cell modules.

Provided is an electrode catalyst in which the contents of chlorine (Cl) species and bromine (Br) species are reduced to a predetermined level or lower, capable of exhibiting sufficient catalyst performance. The electrode catalyst has a core-shell structure including a support, a core part formed on the support and a shell part formed to cover at least a part of the surface of the core part. A concentration of bromine (Br) species of the electrode catalyst as measured by X-ray fluorescence (XRF) spectroscopy is 400 ppm or less, and a concentration of chlorine (Cl) species of the electrode catalyst as measured by X-ray fluorescence (XRF) spectroscopy is 900 ppm or less.

In a method of producing a membrane electrode assembly, a solid polymer electrolyte membrane and gas diffusion layers are stacked together in a stacking direction in a manner that electrode catalyst layers are interposed between at least parts of the solid polymer electrolyte membrane and the gas diffusion layers to form a stack body. A load is applied to the stack body in the stacking direction, and the temperature of the solid polymer electrolyte membrane is increased by high frequency dielectric heating. In this manner, the gas diffusion layers, the electrode catalyst layers, and the solid polymer electrolyte membrane are joined integrally to obtain the membrane electrode assembly.

An electrochemical module (EM) transfers a fluid across a membrane thereof using oxygen as a carrier gas. The EM has an anion exchange membrane (AEM) disposed between a first and second electrodes, each of which includes a catalyst. At an inlet side, the catalyst facilitates reaction of the fluid with carrier gas, such that an anion is formed. The anion is transported across the AEM in the presence of an electric field applied to the electrodes. At an outlet side, the catalyst facilitates dissociation of the anion back to the fluid and carrier gas. In some embodiments, the fluid comprises carbon dioxide, and the transporting by the EM is part of a heating/cooling cycle or a power generation cycle, or is used to capture carbon dioxide for storage or regeneration of stale air. In some embodiments, the fluid comprises water vapor, and the transporting by the EM dehumidifies air.

Systems and methods are provided for using fuel cell staging to reduce or minimize variations in current density when operating molten carbonate fuel cells with elevated CO.sub.2 utilization. The fuel cell staging can mitigate the amount of alternative ion transport that occurs when operating molten carbonate fuel cells under conditions for elevated CO.sub.2 utilization.

Systems and methods are provided for maintaining and/or improving operating lifetime for molten carbonate fuel cells that contain reforming catalyst in the anode when processing cathode input flows that contain sulfur oxides. The systems and methods can include a serial arrangement of molten carbonate fuel cells, where a first fuel cell includes a reduced or minimized amount of reforming catalyst in the anode. A second molten carbonate fuel cell can include reforming catalyst in the anode.

A method for capturing carbon dioxide comprises introducing a first feed stream comprising carbon dioxide and dioxygen into a first electrochemical cell, reducing the carbon dioxide to carbonate ions at a first cathode of the first electrochemical cell, and reducing the carbonate ions at a first anode to produce a first product stream comprising concentrated carbon dioxide and a second product stream comprising water. A second feed stream comprising water is introduced to a second electrochemical cell coupled to the first electrochemical cell. The water is oxidized at a second anode of the second electrochemical cell to produce hydrogen ions and dioxygen gas, the hydrogen ions are reduced to hydrogen gas at a second cathode, and the hydrogen gas produced by the second cathode is transported to the first anode. The first product stream is removed from the first electrochemical cell. Additional methods and related systems are also disclosed.

A molten carbonate fuel cell assembly includes a cathode electrode; an anode electrode; an electrolyte matrix disposed between the cathode electrode and the anode electrode; a cathode current collector abutting the cathode electrode; and a first electrolyte composition stored in the cathode electrode, the first electrolyte composition comprising a first mixture of a eutectic Li/Na carbonate electrolyte doped with one or more additive materials, wherein the one or more additive materials comprise one or more of SrO, BaCO.sub.3, BaO, SrCO.sub.3, and combinations thereof.

A fuel cell system includes a fuel cell having a cathode and an anode configured to receive a portion of a hhydrocarbon feed and to output an anode exhaust stream comprising carbon dioxide, hydrogen, and water; and an electrolyzer cell having a cathode and an anode. The anode of the electrolyzer cell is configured to receive a first portion of the anode exhaust stream and another portion of the hydrocarbon feed, and to generate a hydrogen stream.

Molten carbonate fuel cells (MCFCs) are operated at elevated pressure to provide increased operating voltage and/or enhanced CO.sub.2 utilization with a cathode input stream having a low CO.sub.2 content. It has been discovered that increasing the operating pressure of a molten carbonate fuel cell when using a low CO.sub.2-content cathode input stream can provide unexpectedly large increases in operating voltage while also reducing or minimizing the amount of alternative ion transport and/or enhancing CO.sub.2 utilization.