Jinnouchi Ryosuke, Kudo Kenji, Kodama Kensaku, Kitano Naoki, Suzuki Takahisa, Minami Saori, Shinozaki Kazuma, Hasegawa Naoki, Shinohara Akihiro
Toyota Central R&D Labs., Inc, Nagakute, Aichi, Japan.
Nat Commun. 2021 Aug 16;12(1):4956. doi: 10.1038/s41467-021-25301-3.
In recent years, considerable research and development efforts are devoted to improving the performance of polymer electrolyte fuel cells. However, the power density and catalytic activities of these energy conversion devices are still far from being satisfactory for large-scale operation. Here we report performance enhancement via incorporation, in the cathode catalyst layers, of a ring-structured backbone matrix into ionomers. Electrochemical characterizations of single cells and microelectrodes reveal that high power density is obtained using an ionomer with high oxygen solubility. The high solubility allows oxygen to permeate the ionomer/catalyst interface and react with protons and electrons on the catalyst surfaces. Furthermore, characterizations of single cells and single-crystal surfaces reveal that the oxygen reduction reaction activity is enhanced owing to the mitigation of catalyst poisoning by sulfonate anion groups. Molecular dynamics simulations indicate that both the high permeation and poisoning mitigation are due to the suppression of densely layered folding of polymer backbones near the catalyst surfaces by the incorporated ring-structured matrix. These experimental and theoretical observations demonstrate that ionomer's tailored molecular design promotes local oxygen transport and catalytic reactions.
近年来，人们投入了大量的研发工作来提高聚合物电解质燃料电池的性能。然而，这些能量转换装置的功率密度和催化活性对于大规模运行而言仍远不能令人满意。在此，我们报告了通过在阴极催化剂层中将一种环状主链基质引入离聚物来提高性能的方法。单电池和微电极的电化学表征表明，使用具有高氧溶解度的离聚物可获得高功率密度。高溶解度使氧气能够渗透到离聚物/催化剂界面，并与催化剂表面的质子和电子发生反应。此外，单电池和单晶表面的表征表明，由于磺酸根阴离子基团对催化剂中毒的缓解作用，氧还原反应活性得到了增强。分子动力学模拟表明，高渗透性和中毒缓解均归因于所引入的环状结构基质对催化剂表面附近聚合物主链密集层状折叠的抑制。这些实验和理论观察结果表明，离聚物的定制分子设计促进了局部氧传输和催化反应。
