Hwang, Chang-Kyu Lee, Kyung Ah Lee, Jiyoung Kim, Youngoh Ahn, Hyunchul Hwang, Wontae Ju, Byeong-Kwon Kim, Jin Young Yeo, Sang Young Choi, Joonmyung Sung, Yung-Eun Kim, Il-Doo Yoon, Ki Ro 2024-01-19T11:03:00Z 2024-01-19T11:03:00Z 2022-08-04 2022-10 2211-2855 https://pubs.kist.re.kr/handle/201004/114530 The configuration of reinforced composite membrane (RCM), composed of porous polytetrafluoroethylene (PTFE) as a mechanical reinforcement and perfluorosulfonic acid (PFSA) as a proton conductive polymer, has gained a large interest due to its promisingly high performance for polymer electrolyte membrane (PEM) fuel cells. However, the inaccessible polymeric nanocomposites in preparing RCMs are still faced with critical challenges associated with immiscible interactions between hydrophilic sulfonate groups in PFSA and the hy-drophobic nanoporous PTFE matrix. Herein, we report a well-refined and facile fabrication strategy for pro-ducing a cross-aligned PTFE (CA-PTFE) framework. The electric-field guided electrospinning enables the creation of unique micron-scale, grid-type PTFE matrix, which is synthesized by annealing of electrospun conjugated polymers, resulting in the removal of carrier polymer and the formation of continuous fibrious structure via fusion of PTFE particles. The CA-PTFE RCM embodying uniformly impregnated PFSA in a grid-type PTFE matrix, facilitates hydration of the membranes, with minimal swelling and efficient diffusion of protons through concentrated sulfonate groups. The CA-PTFE RCM adopted cell showed outstanding fuel cell currents during both low and high humidity operation, with a current density of 1.38 A cm-2 at 0.6 V and maximum power density of 0.85 W cm-2 under RH 100% condition. Furthermore, the CA-PTFE RCM was able to achieve a long-lasting single-cell operation with a significantly low hydrogen crossover (less than 5 mA cm-2 at 0.4 V) even after 21,000 wet/dry cycles, which surpasses the standard of membrane durability for transportation application. The rational design of fibrous PTFE reinforcements opens up new engineering opportunities for the future devel-opment of high-stability PEM fuel cells. English ELSEVIER Perpendicularly stacked array of PTFE nanofibers as a reinforcement for highly durable composite membrane in proton exchange membrane fuel cells Article 10.1016/j.nanoen.2022.107581 1 NANO ENERGY, v.101 NANO ENERGY 101 Y scie scopus 000829487500002 Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Chemistry Science & Technology - Other Topics Materials Science Physics Article PACKED-ACID STRUCTURE MECHANICAL-PROPERTIES ELECTROLYTE MEMBRANES NUMERICAL-SIMULATION MOLECULAR-DYNAMICS HIGH-TEMPERATURE ION-TRANSPORT DEGRADATION DURABILITY Cross-alignedPTFEnanofibers Electric-fieldguidedelectrospinning Polymerelectrolytemembranefuelcells Highlydurablecompositemembrane Lowhydrogencrossover