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Assessing cell polarity reversal degradation phenomena in PEM fuel cells by ele...

Electrochemical impedance spectroscopy (EIS) is identified as one of the most promising in-situ diagnostics tools available for assessing fuel cell ageing and degradation. In this work, the degradation phenomena caused by cell polarity reversal due to fuel starvation of an open cathode 16 membrane electrode assembly (MEA) – low power (PEM) fuel cell (15 W nominal power) – is reported using EIS as a base techni...

Assessing cell polarity reversal degradation phenomena in PEM Fuel Cells by ele...

The mechanisms of fuel cell degradation are multiple and not well understood. Irreversible changes in the kinetic and/or transport properties of the cell are fostered by thermal, chemical and mechanical issues which constrain stability, power and fuel cell lifetime. Within the in-situ diagnostics methods and tools available, in-situ electrochemical impedance spectroscopy (EIS) is within the most promising to be...

Polarity reversal by fuel starvation in PEM Fuel Cells

In this work, the degradation caused by polarity reversal by fuel starvation of a 16 MEA (membrane-electrode assembly) – low power PEM fuel cell is reported. Measuring of the potential of individual cells, while on load, was found instrumental in the location of affected cells which revealed very low or even negative potential. Ex-situ analysis of MEA, after irreversible degradation by fuel starvation, gave as ...

Polarity reversal in PEM Fuel Cells by fuel starvation

In this work, the degradation caused by polarity reversal by fuel starvation of a 16 MEA – low power fuel cell is reported. Measuring of the potential of individual cells, while on load, was found instrumental in the location of affected cells which revealed very low or even negative potential. Electrochemical impedance spectroscopy insitu gave insight on the increase in resistance and diffusion processes. Ex-s...

Fuel cell materials degradation in stack configuration

Inibição da corrosão de ligas estructurais de alumínio por hidróxidos duplos la...

Fuel Starvation: irreversible degradation mechanisms in PEM Fuel Cells

PEM fuel cell operates under very aggressive conditions in both anode and cathode. Failure modes and mechanism in PEM fuel cells include those related to thermal, chemical or mechanical issues that may constrain stability, power and lifetime. In this work, the case of fuel starvation is examined. The anode potential may rise to levels compatible with the oxidization of water. If water is not available, oxidatio...

Environmental impact assessment of the penetration of hydrogen technologies in ...

Road traffic is one of the transportation sectors with faster growth and also one of the most important emitters of greenhouse gases (GHGs). In this work, an analysis of the environmental benefits resulting from the introduction of hydrogen on road transport in Portugal is made. Impact is analyzed mainly looking at the pollutant emissions provided by road transport at the point of use. Emissions associated to r...

LUCIS:a learning experience to improve lifetime and operating strategies in low...

LUCIS, a demonstration project co-financed by the Innovation Agency in Portugal (AdI), was carried out in the framework of the DEMTEC Programme (Incentives to Technologically Innovative Pilot Systems). Its main goals were: Validate the reliability of proton exchange membrane fuel cells (PEMFC) when used in practical situations and the competitive advantages that these solutions can represent compared to convent...

Corrosion inhibition of aluminium alloys by layered double hydroxides: the role...

Layered double hydroxides represented by the general formula [M2 2+M3+(OH)6]+X1/n n-.zH2O are being researched as anion-exchange materials with interesting intercalation chemistry that accommodate a wide range of applications, including corrosion resistance. In this work, it is shown that the formation of layered double hydroxides (LDHs) on the surface of copper-rich Al alloys promotes corrosion resistance. For...