Sharma Raghunandan, Morgen Per, Larsen Mikkel Juul, Roda-Serrat Maria Cinta, Lund Peter Brilner, Grahl-Madsen Laila, Andersen Shuang Ma
Department of Green Technology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
IRD Fuel Cells A/S, Emil Neckelmanns Vej 15 A&B, 5220 Odense SØ, Denmark.
ACS Appl Mater Interfaces. 2023 Oct 18;15(41):48705-48715. doi: 10.1021/acsami.3c11186. Epub 2023 Oct 3.
We have developed a recovery, regeneration, and reapplication process for Nafion, a perfluorinated sulfonic acid (PFSA) ionomer, from end-of-life (EoL) low-temperature proton-exchange membrane (PEM) fuel cells (FCs). Samples of PFSA PEM recovered from EoL membrane-electrode assemblies (MEAs) with a history of close to 19,000 h of operation were recycled by dissolving the polymeric material in ethanol and applying the dissolved PFSA ionomer for producing the ionomer phase of the catalyst layer of new PEMFC cathodes. Structural characterizations show a marginally lower abundance of sulfonic groups for the EoL PEM compared to a fresh sample. Sulfonation of the former was employed to regenerate sulfonic groups to compensate for the lost ones. New gas-diffusion electrodes (GDEs) were prepared with the recycled PFSA ionomer both with and without sulfonation, and MEAs with these GDEs as cathodes were assembled through a state-of-the-art procedure. Electrochemical characterizations of the GDEs and single-cell studies of the MEAs showed that the electrochemical performances of catalyst layers containing recycled PFSA ionomer were at least similar to those containing fresh. Durability studies of the GDEs and MEAs, performed through a three-electrode liquid cell and a single cell, respectively, show the highest durability for the GDE/MEA with PFSA ionomer recycled without applying the sulfonation step. However, the GDE with PFSA ionomer obtained from recycling a re-sulfonated PEM shows a durability comparable to that of the GDE with fresh PFSA ionomer. Hence, PFSA material aged during PEMFC operation may be employed to produce highly functional and durable regenerated PFSA ionomer for PEMFC catalyst layers. The studied process of PFSA ionomer recycling is highly attractive for industrial adoption.
我们已开发出一种从报废的低温质子交换膜（PEM）燃料电池（FC）中回收、再生和重新应用全氟磺酸（PFSA）离聚物Nafion的工艺。从运行历史接近19000小时的报废膜电极组件（MEA）中回收的PFSA PEM样品，通过将聚合物材料溶解在乙醇中进行循环利用，并将溶解的PFSA离聚物用于制备新型PEMFC阴极催化剂层的离聚物相。结构表征表明，与新鲜样品相比，报废PEM的磺酸基团丰度略低。对前者进行磺化以再生磺酸基团，以补偿损失的磺酸基团。使用经过循环利用的PFSA离聚物（有磺化和无磺化两种情况）制备了新的气体扩散电极（GDE），并通过先进工艺组装了以这些GDE作为阴极的MEA。GDE的电化学表征和MEA的单电池研究表明，含有循环利用的PFSA离聚物的催化剂层的电化学性能至少与含有新鲜PFSA离聚物的催化剂层相似。分别通过三电极液池和单电池对GDE和MEA进行的耐久性研究表明，未进行磺化步骤循环利用PFSA离聚物的GDE/MEA具有最高的耐久性。然而，通过回收再磺化的PEM获得的含有PFSA离聚物的GDE显示出与含有新鲜PFSA离聚物的GDE相当的耐久性。因此，在PEMFC运行过程中老化的PFSA材料可用于生产用于PEMFC催化剂层的高功能性和耐用性的再生PFSA离聚物。所研究的PFSA离聚物循环利用工艺对工业应用极具吸引力。
