Effect of polymer-coating on acetylene black for durability of polymer electrolyte membrane fuel cell

Abstract

The use of carbon materials having high crystallinity for the electrocatalyst is promising approach to improve durability of the polymer electrolyte membrane fuel cells (PEMFC) due to their excellent electrochemical stability. Polymer-coating on the surface of the carbon materials has been proposed as a unique method to deposit Pt nanoparticles homogeneously on such carbon materials. In this study, effect of the polymer-coating for the stability of Pt nanoparticle upon durability tests of the PEMFC is investigated. Pt nanoparticles deposited on the polybenzimidazole (PBI)-coated acetylene black (AB) is prepared and is used as an electrocatalyst in membrane-electrode-assembly (MEA). Accelerated durability tests (ADT) of MEA between 0.6 and 1.0 V are carried out using H2 and N2 in anode and cathode, respectively, and it is found that MEA employing PBI-coated AB shows only 8% decrease in the maximum power density, while MEA containing non-coated AB shows 34% decrease after the ADT. Structural analysis of the electrocatalysts after the ADT reveals that the PBI anchors both Pt nanoparticle and ionomer upon ADT and maintains their interfacial structure. We conclude that the polymer-coating method is promising both for the improvement of the durability and the activity of the PEMFC.