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 (RLocal), 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 RLocal, while concurrently delineating prospective for future research endeavors in this domain. Commencing with an elucidation of the genesis of RLocal, the micro-characterization technologies in discerning Pt/ionomer interface structure are systematically scrutinized. Subsequently, a retrospect of methodologies and theoretical models for quantifying RLocal is presented, encompassing both experimental test and numerical simulation. After that, we critically examine a spectrum of innovative and efficacious strategies aimed at mitigating RLocal, 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 RLocal in future investigations, which significantly contribute to the cognition of local oxygen transport and, concomitantly, design of high-performance fuel cell electrodes.