Efficient CO ₂ Removal by Improving Diffusion Layer Structure in Direct Methanol Fuel Cells

The two‐phase flow between CO ₂ gas and methanol solution in the anode of passive direct methanol fuel cells (DMFCs) significantly limits cell performance. While considerable progress has been made in mitigating CO ₂ bubble resistance in the anode flow field (AFF), effectively reducing the negative impact of CO ₂ within the membrane electrode assembly (MEA) remains challenging. In this study, we propose a novel anode gas diffusion layer (AGDL) structure designed to overcome two‐phase flow effects within the MEA. The AGDL consists of carbon paper hydrophobically treated with 50 wt% PTFE, featuring lateral venting channels for CO ₂ release and a central hole for methanol supply. Through combined simulation and experimental validation, we demonstrate that physically separating the gas diffusion path and fuel supply path within the AGDL effectively enhances cell performance. The proposed AGDL provides a stable operating environment by mitigating two‐phase flow inside the cell and achieves a maximum power density of 17.3 mW cm ⁻² at 12.0 M methanol concentration, outperforming conventional DMFCs.