质子交换膜燃料电池气体扩散层改性及其氧传质性能研究

Modification of Gas Diffusion Layer for Proton Exchange Membrane Fuel Cell and Its Oxygen Transport Resistance

通过电化学表面沉积的方法在碳纤维表面沉积一层有导电性的1,5-二氨基蒽醌(PDAAQ),再经过高温热处理,在碳纤维表面形成PDAAQ包覆层,制备了一种新型的质子交换膜燃料电池气体扩散层。由改性后的气体扩散层装配的单电池在铂载量为0.5mg/cm^(2)的情况下最高电流密度可以达到3800mA/cm^(2),功率密度达到1.62W/cm^(2),超出了丰田Mirai车和我国重点研发计划的指标要求。通过SEM观察到PDAAQ在碳纤维表面均匀的包覆,除了提供疏水性外还保证了一定的孔隙度。氧传质阻力研究结果证明,经过PDAAQ改性后的基底层有着更低的氧传质阻力,保证了这种经过结构改性的气体扩散层在高电流密度仍然有着良好的性能。

A conductive polymer material 1,5-diaminoanthraquinone(PDAAQ)was synthesized on the carbon fiber of carbon paper by electrochemical deposition method.After heat treatment,the PDAAQ coating layer was created on the surface of the carbon fiber.Using this modified carbon paper as substrate layer,a novel gas diffusion layer for proton exchange membrane fuel cell was prepared.The single cell test results show a current density of 3800mA/cm^(2) with a power density of 1.62W/cm^(2) under Pt loading of 0.5mg/cm^(2),indicating that this modified gas diffusion layer has excellent performance in a proton exchange membrane fuel cell.This MEA power density is higher than that of the DOE and Mirai.SEM images show that the PDAAQ was uniformly coated on the carbon fiber surface,which makes this kind of gas diffusion layer have better porosity than the traditional one,and ensures better air permeability.The measurement of oxygen transport resistance confirmed that the PDAAQ modified substrate of gas diffusion layer has lower oxygen transport resistance,which allows the gas diffusion layer after structure modified to perform well at high current density.