In various aspects, systems and methods are provided for operating molten carbonate fuel cells with processes for iron and/or steel production. The systems and methods can provide process improvements such as increased efficiency, reduction of carbon emissions per ton of product produced, or simplified capture of the carbon emissions as an integrated part of the system. The number of separate processes and the complexity of the overall production system can be reduced while providing flexibility in fuel feed stock and the various chemical, heat, and electrical outputs needed to power the processes.

An electrochemical cell includes: a metal substrate having a principal surface and a plurality of connecting holes formed in the principal surface; and a cell body disposed on the principal surface. The cell body has: a gas diffusion layer disposed on the principal surface, the gas diffusion layer being electrically conductive; a first electrode layer disposed on the gas diffusion layer; a second electrode layer; and an electrolyte layer disposed between the first electrode layer and the second electrode layer. The metal substrate has: a gas-permeable region in which the plurality of connecting holes are formed; and a non-gas-permeable region surrounding the gas-permeable region in a plan view. The gas diffusion layer has: a first region formed on the gas-permeable region; and a second region formed on the non-gas-permeable region. The second region has a crack-preventing space in a cross section along a thickness direction.

An apparatus includes: an electrolyte membrane; a cathode catalyst layer provided to one main surface of the electrolyte membrane; an anode catalyst layer provided to the other main surface of the electrolyte membrane; a cathode gas diffusion layer provided on a main surface of the cathode catalyst layer not facing the electrolyte membrane; a separator including a recess through which cathode gas flows; an anode gas diffusion layer provided on a main surface of the anode catalyst layer not facing the electrolyte membrane; a voltage applicator applying a voltage between the cathode catalyst layer and the anode catalyst layer; and a fastener fastening a laminated body. The cathode gas diffusion layer is accommodated in the recess, projects from the recess in a thickness direction before fastening of the laminated body, and includes an elastic member between side surfaces of the cathode gas diffusion layer and of the recess.

Systems and methods are provided for capturing CO.sub.2 from a combustion source using molten carbonate fuel cells (MCFCs). At least a portion of the anode exhaust can be recycled for use as a fuel for the combustion source. Optionally, a second portion of the anode exhaust can be recycled for use as part of an anode input stream. This can allow for a reduction in the amount of fuel cell area required for separating CO.sub.2 from the combustion source exhaust and/or modifications in how the fuel cells can be operated.

In various aspects, systems and methods are provided for operating a molten carbonate fuel cell assembly at increased power density. This can be accomplished in part by performing an effective amount of an endothermic reaction within the fuel cell stack in an integrated manner. This can allow for increased power density while still maintaining a desired temperature differential within the fuel cell assembly.

Example biosensor devices having wake-up batteries and associated methods are disclosed. One example device includes a biosensor that has a first electrode for insertion into a subcutaneous layer beneath a patient's skin, and a second electrode coupled to the first electrode for insertion into the subcutaneous layer, and a first battery to apply a voltage across the first and second electrodes, the first battery at least partially electrically decoupled from the electrodes. The device also includes a second battery having an anode material coupled to the first electrode for insertion into the subcutaneous layer, and a portion of the second electrode. The second battery is activatable upon immersion in an electrolytic fluid. The device also includes a wake-up circuit to receive a signal from the second battery and, in response, to electrically couple the first battery to the first and second electrodes to activate the biosensor.

In various aspects, systems and methods are provided for operating a molten carbonate fuel cell assembly at increased power density. This can be accomplished in part by performing an effective amount of an endothermic reaction within the fuel cell stack in an integrated manner. This can allow for increased power density while still maintaining a desired temperature differential within the fuel cell assembly.

In various aspects, systems and methods are provided for integration of molten carbonate fuel cells with a Fischer-Tropsch synthesis process. The molten carbonate fuel cells can be integrated with a Fischer-Tropsch synthesis process in various manners, including providing synthesis gas for use in producing hydrocarbonaceous carbons. Additionally, integration of molten carbonate fuel cells with a Fischer-Tropsch synthesis process can facilitate further processing of vent streams or secondary product streams generated during the synthesis process.

In various aspects, systems and methods are provided for operating molten carbonate fuel cells with processes for iron and/or steel production. The systems and methods can provide process improvements such as increased efficiency, reduction of carbon emissions per ton of product produced, or simplified capture of the carbon emissions as an integrated part of the system. The number of separate processes and the complexity of the overall production system can be reduced while providing flexibility in fuel feed stock and the various chemical, heat, and electrical outputs needed to power the processes.

In various aspects, systems and methods are provided for integration of molten carbonate fuel cells with a Fischer-Tropsch synthesis process. The molten carbonate fuel cells can be integrated with a Fischer-Tropsch synthesis process in various manners, including providing synthesis gas for use in producing hydrocarbonaceous carbons. Additionally, integration of molten carbonate fuel cells with a Fischer-Tropsch synthesis process can facilitate further processing of vent streams or secondary product streams generated during the synthesis process.