Technical Strategies on Building Loosened Polymertic-Chain Structure at Platinum-Perfluorinated Sufonicacid Ionomer Interface

For a complete electrification of transportation sector, the hydrogen fuel cells and lithium-ion batteries are considered as promising candidates for electro-chemical energy storage and conversion devices that may utilize the renewable energy. Between them, the PEFCs offer the decisive advantages, such as faster fueling and longer driving range that is especially advantageous for the heavy-duty applications. However, the spread of this technology is blocked by scarcity of platinum group metals (PGMs). Although the state-of-the-art fuel cell electric vehicles (FCEVs) have succeeded in reducing the PGM usage around 20 g per a passenger vehicle until now, over four-folds amount of PGMs must be further reduced to achieve sustainability. Hence, increasing Pt utilization rate in such system is key to everything; however, the performance of PEFC electrode has been severely aggravated under the presence of perfluorinated sulfonicacid (PFSA) ionomer. In this work, we have shown the key comparative features of technical approaches that have been made within literatures in the recent decade including our previous work. More specifically, the electrode ionomer homogeneity of hydrophilic-hydrophobic domains as well as polymeric chain densification at Pt-ionomer interface has been discussed. Finally, some technical pathways to simultaneously resolve the dry accessibility as well as specific adsorption of ionomer are drawn with detailed information. This paper provides a key summary that may be helpful in defining the notorious "RDE versus MEA" issue and also categorizing the possible solutions that are either previously done or will be covered in the near future.