Publications by authors named "Young-Gi Yoon"

Article Synopsis
  • Hexagonal boron nitride (h-BN) and graphene are being explored as effective materials for proton exchange membranes due to their high proton conductivity and stability, but defects during production hinder their use.
  • This study presents a proton exchange membrane using large-area single-oriented AA'-stacked trilayer h-BN (3L-BN), which showed fewer defects and better performance than traditional Nafion-based membranes in fuel cells.
  • The AA'-stacked 3L-BN membrane maintained strong performance after 100 hours of testing, outperforming both Nafion and single-layer h-BN membranes by preventing gas crossover and reactive radical generation.
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In this study, we report self-assembled nitrogen-doped fullerenes (N-fullerene) as non-precious catalysts, which are active for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), and thus applicable for energy conversion and storage devices such as fuel cells and metal-air battery systems. We screen the best N-fullerene catalyst at the nitrogen doping level of 10 at%, not at the previously known doping level of 5 or 20 at% for graphene. We identify that the compressive surface strain induced by doped nitrogen plays a key role in the fine-tuning of catalytic activity.

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A critical issue for maintaining long-term applications of polymer electrolyte fuel cells (PEFCs) is the development of an innovative technique for the functionalization of a carbon support that preserves their exceptional electrical conductivity and robustly enriches their durability. Here, we report for the first time how the formation of a partially coated, ultrathin, hydrophobic silica layer around the surfaces of the carbon nanofiber (CNF) helps improve the durability of the CNF without decreasing the significant electrical conductivity of the virgin CNF. The synthesis involved the adsorption of polycarbomethylsilane (PS) on the CNF's sidewalls, followed by high temperature pyrolysis of PS, resulting in a highly durable, conductive carbon support in PEFCs.

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