Structural Tuning of PGM-Free Electrocatalyst for the High Performance of Membrane Electrode Assembly in PEFCs

Abstract

A non-platinum group metal (PGM) catalyst is one of the promising candidates to reduce the cost of polymer electrolyte fuel cell (PEFC) systems. In our previous work, we reported an excellent ORR activity of porphyrinic carbon based PGM-free catalysts. However, we found a discrepancy of performance between the half-cell and the membrane electrode assembly (MEA) evaluation. Our previous PGM-free catalyst showed unsatisfactory cell performance in the MEA because of several technical barriers such as a low electrical conductivity, insufficient effective active site, and poor oxygen mass transport through the small pore structure. In this study, we redesigned the morphology of PGM-free catalysts which can enhance the effective active sites and electrical conductivity by modifying the design of synthetic process. As a result, we could get a dramatically enhanced MEA performance showing over 600 mW/cm2 of peak power density which can be considered as one of the highest PGM-free MEA performance in this field till now.