Effecr of interfacial adhesion layer on high temperature polymer fuel cells for long-term stability improvement

Abstract

PEMFC is known as one of the most promising candidates for alternative energy source. However it still has problems of catalyst poisoning and water management. To overcome these problems, Phosphoric acid doped PBI membrane which operates in high temperature operation (100~200℃) is recommended. However, it is well known that PBI fuel cell shows significant performance drop in initial stage of on/off operation. Therefore, porous interfacial adhesion layer was introduced between membrane-electrode interfaces to prevent acid dissolution. Porous cross-linked polymer was successfully synthesized from epoxy monomer bisphenol A diglycidyl ether and ammonium carbonate pore former. And the polymer introduced to MEA cathode in which water molecules are generated. As a result, it was identified that the interfacial adhesion layer effectively prevented the OCV drop in initial operation during 20 days. This result means that the membrane damage which results in OCV drop is much reduced. The robust interfacial layer prevents severe volume change of electrolyte by temperature change, and hinders direct contact between electrolyte and liquid water produced in cathode. But the porous interfacial layer did not hinder the proton conduction. Interfacial layer introduced MEA did not showed clear performance deterioration. Therefore, better long-term operation of PBI fuel cell is expected.