Abstract: In the context of the global energy transition and the increasingly severe environmental issues, proton exchange membrane fuel cell (PEMFC) has attracted widespread attention due to its high efficiency and low emission characteristics. The gas diffusion layer (GDL) plays a vital role in PEMFCs by enhancing gas dispersion, facilitating water and thermal management, and providing mechanical support. However, traditional GDLs suffer from issues such as high brittleness, weak water management capability, and high resistance, all of which can lead to reduced cell performance. This study first prepared multilayer composite polyacrylonitrile (PAN)-based fiber membranes by altering the concentration of the spinning solution and employing sequential electrospinning technology. These fiber membranes were then treated by pre-oxidation and carbonization to obtain PAN-based carbon fiber membranes (CFM). Hydrophobic treatments were performed using two different methods: immersion in 1H,1H,2H,2H-perfluorodecyltrichlorosilane (PFTs) solution or treatment by steam. Comprehensive physicochemical properties of the CFMs were tested, and polarization curves and power density curves of fuel cells were measured. The study results indicated that the proe sizes of CFM fibers in single-layer, double-layer, and triple-layer structures decreased from 0.592 μm to 0.395 μm and 0.317 μm, showing a decreasing trend. Tensile strength peaked at 9.39 MPa in double-layer configurations and dropped to 5.26 MPa in triple-layer configurations. For CFMs with the same number of layers, those prepared with increasing spinning solution concentrations exhibited superior mechanical and electrical performance compared to those prepared with decreasing concentrations. Hydrophobic treatment by immersing in 0.5 g PFTs for 1 hour can significantly enhance the water management capability of the gas diffusion layer (GDL). Compared to single-layer and triple-layer GDLs, the double-layer structured GDL exhibited the highest power density of 0.520 W/cm2. This study provides new methods for the preparation of gas diffusion layers in proton exchange membrane fuel cell.

Key words: proton exchange membrane fuel cells, gas diffusion layer, hydrophobic treatment, electrospinning, multilayer composites

摘要： 在全球能源转型和环境问题日益严峻的背景下，质子交换膜燃料电池(PEMFC)因其高效率、低排放特性受到广泛关注。气体扩散层(GDL)作为PEMFC的核心组件，不仅可促进气体分散和水分管理，还为电池提供必要的机械支持。然而，传统GDL存在脆性大、水管理能力弱和界面电阻高等问题。本研究通过改变纺丝液浓度，运用分步静电纺丝技术制备多层复合聚丙烯腈纤维膜，经预氧化和碳化处理后获得碳纤维膜(CFM)，并采用1H,1H,2H,2H-十三氟-N-辛基硅烷(PFTs)溶液浸泡或蒸汽处理实现其表面疏水改性。通过系统测试CFM的理化特性及燃料电池极化曲线、功率密度曲线，揭示了结构参数与性能的关联。研究结果表明，单层、双层及三层结构的CFM平均孔径分别为0.592, 0.395和0.317 μm，呈现递减趋势。拉伸强度随层数增加先增加后下降，从单层的4.99 MPa增至双层的9.39 MPa然后降至三层的5.26 MPa。对于相同层数的CFM，递增纺丝液浓度制备的CFM在机械性能和导电性能方面均优于递减纺丝液浓度制备的CFM。使用0.5 g PFTs进行1 h的浸泡疏水处理显著提升了GDL的水管理能力。相比单层和三层GDL，双层结构的GDL表现出最高的功率密度，为0.520 W/cm2。本项研究为质子交换膜燃料电池中气体扩散层的制备提供了新的方法和思路。

关键词: 质子交换膜燃料电池, 气体扩散层, 疏水处理, 静电纺丝, 多层复合