Composition optimization of carbon black and carbon nanotubes for enhancing water management in fuel cells

The newly prepared gas diffusion layers (GDLs) were prepared and characterized in this paper. Carbon black (Vulcan XC-72) and carbon nanotubes (CNTs) were combined in two completely different ratios to create microporous layer (MPL). The GDL prepared exhibited excellent hydrophobicity and low resistivity as demonstrated by water contact angle tests and resistivity measurements. Different ratios of the conductive carbon black Vulcan XC-72 and carbon nanotubes affected the performance of fuel cell as shown by polarization curves and electrochemical impedance spectroscopy. Separately, the mercury intrusion test revealed that the newly altered aperture size distribution of the newly prepared GDLs was responsible for the shift in fuel cell performance. The MPL with 50% each of Vulcan XC-72 and carbon nanotubes had more 7-20 mu m and 20-100 mu m pores compared to commercial GDL, which improved proton exchange membrane fuel cell's ability to control water and gas. The highest power density increased by 18.5% over commercial GDL at 60% humidity, and increased by 13.2% at 100% humidity.