E. Simonetti

Development and characterization of novel cathode materials for molten carbonate fuel cell

Abstract In the development of molten carbonate fuel cell (MCFC) technology, the corrosion of materials is a serious problem for long-term operation. Indeed, slow dissolution of lithiated-NiO cathode in molten carbonates is the main obstacle for the commercialization of MCFCs. In the search of new, more stable, cathode materials, alternative compounds such as LiFeO2, Li2MnO3, and La1−xSrxCoO3 are presently under investigation to replace the currently used lithiated-NiO. The aim of the present work was to investigate the possibility to produce electrode based on LiCoO2, a promising cathode material. At first, LixCoO2 power samples (0.8

Molten carbonate fuel cells fed with biogas: Combating H2S

The use of biomass and waste to produce alternative fuels, due to environmental and energy security reasons, is a high-quality solution especially when integrated with high efficiency fuel cell applications. In this article we look into the coupling of an anaerobic digestion process of organic residues to electrochemical conversion to electricity and heat through a molten carbonate fuel cell (MCFC). In particular the pathway of the exceedingly harmful compound hydrogen sulphide (H(2)S) in these phases is analysed. Hydrogen sulphide production in the biogas is strongly interrelated with methane and/or hydrogen yield, as well as with operating conditions like temperature and pH. When present in the produced biogas, this compound has multiple negative effects on the performance and durability of an MCFC. Therefore, there are important issues of integration to be solved. Three general approaches to solve the sulphur problem in the MCFC are possible. The first is to prevent the formation of hydrogen sulphide at the source: favouring conditions that inhibit its production during fermentation. Secondly, to identify the sulphur tolerance levels of the fuel cell components currently in use and develop sulphur-tolerant components that show long-term electrochemical performance and corrosion stability. The third approach is to remove the generated sulphur species to very low levels before the gas enters the fuel cell.

Development of molten carbonate fuel cell using novel cathode material

The slow dissolution of lithiated-NiO cathodes in molten carbonates is the main obstacle for the commercialization of molten carbonate fuel cells. The aim of the present work was to investigate the possibility of producing an electrode based on LiCoO2. The LixCoO2 powder samples (0.8 < x < 1.1) were obtained by thermal decomposition of carbonate, acetate and oxide precursors, in air. The syntheses were monitored by thermal analysis (TGA, DTA). The calcined and sintered powder samples were characterized by X-ray diffraction and atomic absorption spectroscopy The porous electrodes were prepared with different pore-formers by cold pressing and sintering. A bi-modal pore size distribution was observed in all the materials. Conductivity measurements were carried out in the temperature range 500–700 °C. The solubility in molten carbonates was measured. To test the cathodic performance of the materials under study, electrochemical impedance spectroscopy measurements were carried out to investigate the porous electrode/molten carbonate interface.

Performance Study of Nickel Covered by Lithium Cobaltite Cathode for Molten Carbonate Fuel Cells: A Comparison in Li/K and Li/Na Carbonate Melts

The slow dissolution of the lithiated NiO cathode represents one of the main causes of performance degradation in molten carbonate fuel cells. Two main approaches are usually investigated to overcome this problem: modifying the electrolyte composition and studying innovative cathode. In this work, the production of an alternative material as well as a study in different carbonate melt mixtures (62/38 mol % Li/K and 52/48 mol % Li/Na) of this innovative cathode have been taken into account. The issue of cathode surface protection was attained covering a nickel substrate with a thin layer of lithium cobaltite doped with magnesium (LiMg 0.05 Co 0 . 95 O 2 ); a sol impregnation technique was used to deposit gel precursors on the porous surface of the substrate. Chemical analysis, electrical conductivity measurements and scanning electron microscopy were used to characterize the cathodes before and after in-cell tests. The cathodic performance was tested in two 3 cm 2 area cells assembled with the following electrolyte compositions: Li/K=62/38 mol % and Li/Na =52/48 mol % in order to investigate the cathode behavior in different carbonate melt environments. Polarization curves and electrochemical impedance spectroscopy measurements were carried out during cell lifetime (about 850 h). Finally, different compositions of the cathodic gas were used to study the influence of oxygen and carbon dioxide on the electrode kinetics.

Evaluation software for fuel cells performance tests

A software to evaluate the performances of fuel cells has been developed The software, initially developed for Molten Carbonate Fuel Cells, allows to realize some measurement tests on it, satisfying flexibility characteristics particularly appreciated by qualified developer and researcher. The software allows to verify both single cells and whole stack by the control of voltage waveform versus time or current. Moreover it can be used also for other kind of fuel cells.