Self-humidification is becoming a popular strategy for water management in proton exchange membrane fuel cells (PEMFCs), owing to the advantages of decreased volume, cost, and parasitic power of the hydrogen fuel cell engine. Membrane dehydration is one of the key issues that seriously affect the performance and lifespan of PEMFCs under low humidity conditions. In this work, an electrospinning approach was employed to fabricate gas diffusion layers (e-GDLs) composed of nanosized carbon fibers with a nanoscale pore structure. Further, a vapor deposition of Dow Corning Sylgard 184 was utilized to apply a hydrophobic coating to enhance the hydrophobicity of the e-GDL. The fabricated e-GDL can help alleviate the dehydration of the catalyst-coated membrane by increasing the breakthrough pressure. The breakthrough pressure of the e-GDL is five folds higher than that of the current commercial GDL, owing to the combined effects of the nanostructure and enhanced hydrophobicity. This superior characteristic is expected to effectively alleviate membrane dehydration under low humidity conditions. In addition, the e-GDL has excellent elastic deformability, which can effectively alleviate the irreversible damage caused by the pre-tightening force in the stack assembly process, thus enhancing the durability and lifetime of PEMFCs.
Ying Wang,Zheng Xie,Weiqi Zhang,Huiyuan Liu,Qian Xu,Lindiwe Khotseng,Huaneng Su
A novel enhanced membrane electrode assembly (MEA) was successfully developed by incorporating a phosphoric acid (PA)-loaded Schiff base network (SNW)-type covalent organic framework (COF) as an additive to the catalyst layer (CL) to improve the performance of proton exchange membrane fuel cells (PEMFCs) under low humidity conditions. The unique network structure and PA-loaded H 3 PO 4 @SNW-1 material have excellent water management and proton transfer abilities. Direct use of this material as a CL additive can significantly enhance the performance of PEMFCs under varying humidification conditions. The optimization of the additive content , the impact of the anode/cathode modification, and the operating temperature of PEMFCs were studied using electrochemical characterization and single cell tests. The maximum power density of MEAs with 15 wt.% H 3 PO 4 @SNW-1 added to the anode CL at a normal operating temperature of 60 °C was 745 mW cm −2 and 690 mW cm −2 under full humidification (100% RH) and low humidification (21% RH), respectively, both of which were higher than that of conventional MEAs. Furthermore, preliminary durability test and 10-day intermittent operation demonstrate the potential of the proposed PEMFCs in actual operation in harsh environments.
危险品化学品经营许可证（带存储）