▎ 摘　　要

NOVELTY - The gas diffusion layer comprises a carbon fiber monofilament and a graphene composite formed porous ventilating conductive carbon material layer, where the porosity is not less than 70%. The conductive carbon material layer comprises a support layer and a microporous layer on the support layer. The support layer comprises a porous material layer formed by compounding the carbon fibre mono filaments with the large graphene. The large graphene is 1-5 graphene atom layers, and the area of the single micro-sheet graphene is greater than 50 square microns USE - Gas diffusion layer formed by carbon fiber and graphene combination. ADVANTAGE - The carbon fiber and graphene composite is featured with high mechanical strength, multi-stage hole gradient distribution, good ventilation, good conductivity, good heat conductivity and light and high stability. The graphene-carbon fiber combined gas diffusion layer is environment-friendly, gaseous emptying is less than carbon paper 99 %. The method is suitable for batch fast preparation of roll-to-roll, which is higher than the flat plate method efficiency of the traditional carbon paper. The mechanical strength of the gas diffusion layers and the supporting layer is greatly improved by more than 2 times, the supporting layers are improved by 1-2 orders of magnitude, the thickness is reduced to 1/2-1/5 of the commercial carbon paper, the heat-conducting performance is improved by 2-5 times, and the DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following; 1. Method for splitting filament by fibre tow; 3. Method for preparing large graphene. DESCRIPTION OF DRAWING(S) - The drawing shows the front photograph and cross section thickness photograph of graphene-carbon fiber monofilament layer of scanning electron microscope photograph.