Carbon cloth gas diffusion layer with carbon nanotube sheet microporous layer for high performance polymer electrolyte membrane fuel cells

Water management and mass transfer capability in high humidity are important factors for the high performance of polymer electrolyte membrane fuel cells (PEMFCs). However, flooding under high humidity and high current density is an important degradation factor for PEMFCs, causing irregular cell performance and negatively affecting durability. To address these issues, we employed a carbon nanotube (CNT) sheet as the microporous layer instead of the commonly used carbon black and used carbon cloth as the gas diffusion backing layer. The nanoporous structure of the CNT sheet enhances the driving force generated by capillary pressure, facilitating water evacuation and improving mass transfer. In addition, the large and regular pore structure of the carbon cloth further aids in water removal. This work demonstrates that a gas diffusion layer (GDL) fabricated using a CNT sheet and carbon cloth leads to a 34.2% improvement in peak power density compared to two types of commercial GDLs. Mass transport overvoltage and antiflooding tests further confirm that our GDL offers superior water evacuation and mass transfer capabilities compared to commercial GDLs. With its exceptional performance and water management capabilities, our GDL is expected to positively impact the commercialization of PEMFCs through its cost-efficient production process.