Polarity reversal in PEM Fuel Cells by fuel starvation

• Autor(es): Travassos, Maria Antónia ; Rangel, C. M.
• Data: 2010
• Identificador Persistente: http://hdl.handle.net/10400.9/1130
• Origem: Repositório do LNEG
• Assunto(s): Polarity reversal; Fuel starvation; PEM degradation; AC impedance characteristic; Morphological defects
• Tipo de Documento: Documento de conferência
• Idioma: Inglês

Descrição

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-situ analysis of MEA after irreversible degradation by fuel starvation gave as a result delamination of catalyst layers with impacts on fuel cell performance such as development of flooded areas by the pockets created increasing the resistance of reactant transport to the catalyst sites. Striking and thickness variation of the anode layer as well as carbon corrosion were found. The proton exchange membrane is also affected by fluoride depletion.