| 摘要 |
<p>A carbon fiber paper usable as a current collector for solid polymer fuel cells, which is out of danger of short-circuiting with a counter electrode, is not destroyed even by pressurizing, exhibits a relatively low resistance, and is inexpensive. Specifically, a carbon fiber paper for solid polymer fuel cells which is used in the cell in a state wherein the short carbon fibers of the paper are bound with a polymeric substance and which is characterized in that at least 95 % of the short carbon fibers excepting those having lengths of (Y + 0.1) mm or below satisfy the relationship: W≥5X, wherein X is the thickness (mm) of the paper, Y is the thickness (mm) thereof under pressurizing at 2.9 MPa, and W is the length (mm) of each short carbon fiber. It is preferable that the short carbon fibers satisfy also the relationship: Z≥5X, wherein Z is the average length (mm) of the short fibers. The carbon fiber paper exhibits a weight loss of 3 % or below as determined by applying a uniform surface pressure of 2.9 MPa in the thicknesswise direction for 2 minutes and releasing the surface pressure, and the short carbon fibers contained in the carbon fiber paper satisfy the following relationship: σ/(E D)≥0.5 10-3, wherein D is the diameter (νm) of the short carbon fibers, σ is the tensile strength (MPa) thereof, and E is the tensile modulus (MPa) thereof.</p> |
