CARBON SUBSTRATE COMPRISING CARBON FIBERS UNIDIRECTIONALLY ALIGNED, AND GAS DIFFUSION LAYER EMPLOYING SAME

Disclosed are a carbon substrate for a fuel cell gas diffusion layer, a gas diffusion layer comprising same, a gas diffusion layer employing same, a fuel cell electrode, a fuel cell membrane electrode assembly, and a fuel cell, the carbon substrate comprising a sheet-shaped substrate having an upper surface and a lower surface on the opposite side thereof, wherein the sheet-shaped substrate comprises carbon fibers which are unidirectionally extended and arranged and an organic polymer carbide between the carbon fibers, binding the carbon fibers to each other. The carbon substrate comprises carbon fibers, which are aligned in at least any one direction, having been selected from among a machine direction (MD) and a cross-machine direction (CMD), by controlling the alignment of carbon fibers, and thus the carbon substrate is thin but has excellent mechanical strength and, particularly, excellent flexural strength, thereby enabling effective prevention of the penetration of a gas diffusion layer into a metal sep