Nanocomposite Engineering and Laser Processing for Gas Diffusion Backing Layers with Enhanced Transport and Conductive Properties in Proton Exchange Membrane Fuel Cells

초록

Efficient mass and charge transport within the gas diffusion layer (GDL) is critical to the overall performance of proton exchange membrane fuel cells (PEMFCs). GDL can be categorized as multifunctional composite structure made of nonwoven carbon fiber paper and nanocarbon composite, and the mechanical, electrical, and electrochemical properties, and hydrophobicity of GDL affect PEMFC performance with its microstructure. In this study, multi-scale design strategies combining laser processing and nanocomposite engineering were employed to simultaneously optimize the structural, electrical, and wetting properties of GDLs. First, a laser-perforated gas diffusion nanocomposite layer (LPM-GDNL) featuring a hydrophilic?superhydrophobic columnar interface was developed to achieve spatially separated water and gas transport. This unique configuration enhanced current and power densities by up to 40% and 50% compared to commercial carbon paper under 50% and 100% relative humidity, respectively. Second, a laser engraving process was optimized to selectively decompose the insulating fluoropolymer layer on gas diffusion nonwoven carbon paper, reducing area-specific resistance by 38% and improving maximum current density by up to 61% under low humidity conditions. Finally, a CNT/PTFE nanocomposite coating was introduced to impart high electrical conductivity and controllable hydrophobicity, achieving a 49% increase in through-plane conductivity while maintaining a contact angle of ~140°. The synergistic combination of laser-induced microstructural modification and nanocomposite surface engineering can demonstrate a promising route for next-generation GDLs with balanced mass transport, electrical conductivity, and water management in PEMFCs.