A high temperature electrolyzer assembly comprising at least one electrolyzer fuel cell including an anode and a cathode separated by an electrolyte matrix, and a power supply for applying a reverse voltage to the at least one electrolyzer fuel cell, wherein a gas feed comprising steam and one or more of CO2 and hydrocarbon fuel is fed to the anode of the at least one electrolyzer fuel cell, and wherein, when the power supply applies the reverse voltage to the at least one electrolyzer fuel cell, hydrogen-containing gas is generated by an electrolysis reaction in the anode of the at least one electrolyzer fuel cell and carbon dioxide is separated from the hydrogen-containing gas so that the at least one electrolyzer fuel cell outputs the hydrogen-containing gas and separately outputs an oxidant gas comprising carbon dioxide and oxygen.

A method of making an electrolyte matrix includes: preparing a slurry comprising a support material, a coarsening inhibitor, an electrolyte material, and a solvent; and drying the slurry to form an electrolyte matrix. The support material comprises lithium aluminate, the coarsening inhibitor comprises a material selected from the group consisting of MnO.sub.2, Mn.sub.2O.sub.3, TiO.sub.2, ZrO.sub.2, Fe.sub.2O.sub.3, LiFe.sub.2O.sub.3, and mixtures thereof, and the coarsening inhibitor has a particle size of about 0.005 m to about 0.5 m.

A hydrogen generation system for generating hydrogen and electrical power includes a power supply, a reformer-electrolyzer-purifier (REP) assembly including at least one fuel cell including an anode and a cathode separated by an electrolyte matrix, at least one low temperature fuel cell, and a hydrogen storage. The at least one fuel cell is configured to receive a reverse voltage supplied by the power supply and generate hydrogen-containing gas in the anode of the at least one fuel cell. The at least one low temperature fuel cell is configured to receive the hydrogen-containing gas output from the REP assembly. The at least one low temperature fuel cell is configured to selectably operate in a power generation mode in which the hydrogen-containing gas is used to generate electrical power and a power storage mode in which the hydrogen-containing gas is pressurized and stored in the hydrogen storage.

A high temperature electrolyzer assembly comprising at least one electrolyzer fuel cell including an anode and a cathode separated by an electrolyte matrix, and a power supply for applying a reverse voltage to the at least one electrolyzer fuel cell, wherein a gas feed comprising steam and one or more of CO2 and hydrocarbon fuel is fed to the anode of the at least one electrolyzer fuel cell, and wherein, when the power supply applies the reverse voltage to the at least one electrolyzer fuel cell, hydrogen-containing gas is generated by an electrolysis reaction in the anode of the at least one electrolyzer fuel cell and carbon dioxide is separated from the hydrogen-containing gas so that the at least one electrolyzer fuel cell outputs the hydrogen-containing gas and separately outputs an oxidant gas comprising carbon dioxide and oxygen.

A caulk composition includes: at least one powder component and at least one binder component. The powder component is a ball-milled powder component comprising ceria, zirconia, alumina, or a combination thereof. The powder component is a heat-treated powder component that has been heated to a temperature of at least 1500 C. The powder component is present in a concentration range of 65 wt % to 75 wt % of the caulk composition. The powder component has a particle size distribution of 95% less than 25 m and 90% greater than 1 m. The binder component is present in a concentration range of 25 wt % to 35 wt % of the caulk composition.

A method of making an electrolyte matrix includes: preparing a slurry comprising a support material, a coarsening inhibitor, an electrolyte material, and a solvent; and drying the slurry to form an electrolyte matrix. The support material comprises lithium aluminate, the coarsening inhibitor comprises a material selected from the group consisting of MnO.sub.2, Mn.sub.2O.sub.3, TiO.sub.2, ZrO.sub.2, Fe.sub.2O.sub.3, LiFe.sub.2O.sub.3, and mixtures thereof, and the coarsening inhibitor has a particle size of about 0.005 m to about 0.5 m.

A caulk composition includes at least one powder component and at least one binder component, such that the powder component has a particle size distribution in the range of 95% less than 25 m and 90% greater than 1 m. A molten carbonate fuel cell (MCFC) includes a fuel cell stack, a manifold, and the caulk composition disposed in between the fuel cell stack and the manifold.

Disclosed are a method for supplying molten carbonate fuel cell with electrolyte and a molten carbonate fuel cell using the same, wherein a molten carbonate electrolyte is generated from a molten carbonate electrolyte precursor compound in a molten carbonate fuel cell and is supplied to the molten carbonate fuel cell.

An electrolyte matrix for use with molten carbonate fuel cells having an enhanced stability and lifetime is provided. The electrolyte matrix includes lithium aluminate as a support material and a coarsening inhibitor. The coarsening inhibitor may be in the form of discrete particles or a dopant present in the support material. The coarsening inhibitor may include MnO.sub.2, Mn.sub.2O.sub.3, TiO.sub.2, ZrO.sub.2, Fe.sub.2O.sub.3, LiFe.sub.2O.sub.3, or mixtures thereof. The coarsening inhibitor prevents the formation of large pores in the electrolyte matrix during operation of the fuel cell, increasing the performance and the service lifetime of the electrolyte matrix.

A fuel cell system includes a fuel cell having a cathode and an anode configured to receive a portion of a hydrocarbon 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.