Exploring local oxygen transport in low-Pt loading proton exchange membrane fuel cells: A comprehensive review

In light of the widespread commercialization of proton exchange membrane fuel cells (PEMFCs) on a global scale, the expeditious resolution of challenges pertaining to cost and performance has become imperative. The strategy of fabricating cathode featuring ultralow Pt loading stands out as a pivotal technical avenue for enhancing the cost competitiveness of PEMFCs. Whereas, within low-Pt electrode, local oxygen transport resistance (R_Local), emanated from the oxygen transport process through the ionomer film positioned on Pt surface, assumes a paramount role in the manifestation of concentration polarization losses. This comprehensive review encapsulates the latest strides in understanding and addressing R_Local, while concurrently delineating prospective for future research endeavors in this domain. Commencing with an elucidation of the genesis of R_Local, the micro-characterization technologies in discerning Pt/ionomer interface structure are systematically scrutinized. Subsequently, a retrospect of methodologies and theoretical models for quantifying R_Local is presented, encompassing both experimental test and numerical simulation. After that, we critically examine a spectrum of innovative and efficacious strategies aimed at mitigating R_Local, including modifying Pt surface, designing carbon support, tuning ionomer, optimizing solvent, and constructing catalyst layer. Finally, this review proffers forward-looking viewpoints on the research orientation and methods of R_Local in future investigations, which significantly contribute to the cognition of local oxygen transport and, concomitantly, design of high-performance fuel cell electrodes.