Structural Modification of a Membrane Electrode Assembly via a Spray Coating in PEMFCs

Abstract

The primary focus of this investigation is to improve water management in polymer electrolyte membrane fuel cells by structural modification of the membrane electrode assembly (MEA). The modified catalyst coated membrane (CCM) type MEA structure is suggested that the direct spraying technique is applied on not only the catalyst layers but also the micro-porous layers. Using electrochemical impedance analysis, the modified structure demonstrates that the charge transfer resistances are exceedingly reduced due to the easy access of reactants to the active sites. This indicates that the void spaces near active sites are thoroughly eliminated through structural modification during which the liquid condensation and gas paths blocking are occurred. This result from the liquid tends to move to the larger pores or void spaces because the capillary pressure increases with a decrease of the pore diameter. Therefore, excess water is removed as fast as possible. As a result, structural modification of the MEA increases performance to more than 20% that of conventional CCM type MEA.