Effect of carbon fiber length on performance of carbon paper used in fuel cell

The carbon fiber is the primary raw material of carbon fiber paper. The length of carbon fiber is the key factor that influences the performance of carbon fiber paper. The effect of the fiber length, between 3 mm to 11 mm, on the performance of carbon fiber paper was discussed in this paper. The results show that the performance of the paper was relatively the best when the length is 5 mm, its performance is as follows: The electrical resistivity (in plane) was 2.5 mΩ·cm, the electrical resistivity (through plane) was 80 mΩ·cm, the tensile strength was 37.5 N/m, the bending strength was 140 MPa, the gas permeability was10.8 ft3/min, the porosity rate was 83%, the diameters of the holes were between 0-25μm, and more than 95% holes were under 20 μm.