Hydrophobic carbon paper and preparation method thereof, gas diffusion layer and fuel cell

The invention relates to hydrophobic carbon paper and a preparation method thereof, a gas diffusion layer and a fuel cell. The preparation method of the hydrophobic carbon paper comprises the following steps: carrying out surface fluorination treatment on the carbon paper by adopting mixed gas of fluorine gas and nitrogen gas; wherein the carbon paper is formed by compounding carbon fibers, and the diameter of the carbon fibers is 5-15 microns; the thickness of the carbon paper is 100 [mu] m-500 [mu] m. The mixed gas of fluorine and nitrogen is used for performing surface fluorination treatment on the carbon fiber material with the specific diameter and the carbon paper with the specific thickness, so that the hydrophobic property of the carbon paper is effectively improved, and the conductivity and the porosity are not influenced. 本发明涉及一种疏水碳纸及其制备方法、气体扩散层和燃料电池，疏水碳纸的制备方法包括如下步骤：采用氟气和氮气的混合气体对碳纸进行表面氟化处理；其中，碳纸由碳纤维复合而成，碳纤维的直径为5μm～15μm；碳纸的厚度为100μm～500μm。通过采用氟气和氮气的混合气体对特定直径碳纤维材质和特定厚度的碳纸进行表面氟化处理，不仅有效提高碳纸的疏水性能，且导电性能和孔隙