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Due to a high conductivity of about 0.1 S·cm−1, Li-Na-K carbonate eutectic and Sm-doped ceria composite material is a good electrolyte candidate for hybrid fuel cells operating between 500 °C and 600 °C. The present paper aims at a deeper understanding of the species and mechanisms involved in the ionic transport through impedance spectroscopy and thermal analyses, in oxidizing and reducing atmospheres, wet and dry, and during two heating/cooling cycles. Complementary structural analyses of post-mortem phases allowed us to evidence the irreversible partial transformation of molten carbonates into hydrogenated species, when water and/or hydrogen are added in the surrounding atmospheres. Furthermore, this modification was avoided by adding CO2 in anodic and/or cathodic compartments. Finally, a mechanistic model of such composite electrical behavior is suggested, according to the surrounding atmospheres used. It leads to the conclusions that cells based on this kind of electrolyte would preferably operate in molten carbonate fuel cell conditions, than in solid oxide fuel cell conditions, and confirms the name of "Hybrid Fuel Cells" instead of Intermediate Temperature (or even Low Temperature) Solid Oxide Fuel Cells. [ABSTRACT FROM AUTHOR]

Summary: Ionic liquids (ILs) are promising solvents for catalytic and electrolyte applications, gas absorption, and extractions in electrochemical systems due to their useful features, such as high conductivity and good thermal, chemical, and electrical stability. This review focuses on incorporating ILs into fuel cell (FC) systems, specifically into two main components of FC (ie, polymer electrolyte membrane and electrocatalyst). In FC, a polymer electrolyte membrane with excellent conductivity and deprived of humidity even at high temperatures must be created for effective early commercialization of this technology. Electrocatalyst performance can also be enhanced with additive materials, such as ILs, thus further improving the entire achievement of FCs. This work discusses the most important reasons for ongoing studies and outlines the current progress in using ILs as a revolutionary form of polymer electrolyte membrane and electrocatalyst. [ABSTRACT FROM AUTHOR]

The paper presents a mathematical model of a molten carbonate fuel cell with a catalyst in the anode channel. The modeled system is fueled by methane. The system includes a model of the steam reforming process occurring in the anode channel of the MCFC fuel cell and the model of the cell itself. A reduced order model was used to describe the operation of the molten carbonate fuel cell, whereas a kinetic model describes the methane steam reforming. The calculations of the reforming were done in Aspen HYSYS software. Four values of the steam-to-carbon ratio (2.0, 2.5, 3.0, and 3.5) were used to analyze the performance of the reforming process. In the first phase, the reaction kinetics model was based on data from the literature. [ABSTRACT FROM AUTHOR]