(Invited) Strategies to Improve the Stability of Fe/N/C Catalysts in PEM Fuel Cells

Abstract

Proton-exchange membrane (PEM) fuel cells hold promising applications in transportation and stationary, however, their widespread commercialization is greatly hindered by the high cost. Platinum (Pt) represents one of the largest cost components of a fuel cell, therefore, my research interests have been focusing on strategies that will increase the activity and utilization of platinum group metal (PGM) catalysts, and improve the performance and stability, as well as prolong the lifetime of the PGM-free catalysts. In this talk, I will first briefly present our work on developing low-PGM catalysts (various unique nanostructured Pt nanowires, nanotubes, and single atoms) to significantly increase the activity and stability of the Pt-based catalysts for ORR in fuel cells. Then, I will mainly focus on our work on PGM-free catalysts. Based on the major breakthroughs on Fe/N/C catalyst achieved by the Dodelet team at INRS (with the MEA activity and performance approaching that of Pt catalyst) [1,2], in collaboration with Ballard Power Systems and Toyota, we have made important progress on improving the stability of PGM-free catalyst [3-17]. Specifically in the following aspects: (i) identifying the active sites, (ii) understanding the fuel cell degradation mechanisms experimentally and theoretically, (iii) developing approaches to improving the stability of the Fe/N/C catalyst, such as pore size control, and fluorination, and (iv) catalyst layer and electrode optimization, such as catalyst hydrophobicity adjustment, Fe/N/C and ultra-low loading Pt/C hybrid catalyst.