烧结温度对PPS和PTFE混合疏水剂微孔层的微观结构及电化学特性的影响

Effect of sintering temperature on the microstructure and electrochemical characteristics of microporous layers containing mixed hydrophobic agents of PPS and PTFE

中文关键词: 质子交换膜燃料电池  微孔层  烧结温度  疏水剂  水管理

英文关键词: proton exchange membrane fuel cell  microporous layer  sintering temperature  hydrophobic agent  water management

中文摘要:

      质子交换膜燃料电池中的微孔层（MPL）通常由疏水剂和碳颗粒高温烧结而成，用于改善电池中的气、水传输。微孔层制备时的烧结温度显著影响其微观结构，进而影响电化学特性。本文通过扫描电镜、孔径分析、接触角测量、极化曲线测试等方法对4种烧结温度（335-400°C）下的聚苯硫醚（PPS）和聚四氟乙烯（PTFE）混合疏水剂制备的MPL的微观结构和电池性能进行表征。结果表明，随着烧结温度的升高，观察到的疏水剂颗粒逐渐减少，说明更多的疏水剂融化且分布更均匀。MPL表面接触角随烧结温度的升高而减小，说明MPL表层疏水剂逐渐减少并流向MPL内部。孔隙率受疏水剂融化程度和疏水剂挥发两方面的影响。335°C和350°C下制备的MPL电化学性能略优于其他两个温度，孔径分布更加均匀。

英文摘要:

      The microporous layer (MPL) in proton exchange membrane fuel cells is typically composed of hy-drophobic agents and carbon particles that are sintered at high temperatures to enhance gas and wa-ter transport within the fuel cell. The sintering temperature during MPL preparation significantly affects its microstructure, thereby influencing its electrochemical properties. This study prepared MPLs containing a mixture of polyphenylene sulfide (PPS) and polytetrafluoroethylene (PTFE) hy-drophobic agents at four different sintering temperatures (335-400°C). The microstructure and fuel cell performance of these MPLs were characterized using techniques such as scanning electron mi-croscopy, pore size analysis, and polarization curves. The results indicate that as the sintering tem-perature increases, the observed hydrophobic agent particles decrease in number, suggesting that a greater amount of the hydrophobic agent melts and achieves a more uniform distribution. The con-tact angle of the MPL surface decreases with increasing sintering temperature, indicating a gradual reduction of hydrophobic agents at the MPL surface, which migrate towards the interior of the MPL. Porosity is affected by both the degree of hydrophobicity melting and hydrophobicity volatilization. The electrochemical properties of MPLs prepared at 335°C and 350°C are slightly better than the other two temperatures, with more uniform pore size distribution.