A carbon substrate, method, and a system for manufacturing the same. The method includes forming an oxidized carbon precursor fiber preweb comprising oxidized carbon precursor staple fibers and binder staple fibers; impregnating the oxidized carbon precursor fiber preweb with a slurry including a thermosetting resin and carbonaceous fillers and drying the resulting preweb to obtain an oxidized carbon precursor fiber web; applying heat and pressure to the oxidized and impregnated carbon precursor fiber web, to cure the thermosetting resin and press the oxidized carbon precursor fiber web; and heating the oxidized carbon precursor fiber web in an inert atmosphere, thereby stabilizing and carbonizing the oxidized carbon precursor staple fibers to obtain a carbon substrate. The present invention may utilize a combination of carbon precursor staple fibers in an oxidized form with low ductility and high stiffness; and binder staple fibers composed of a polymer resin.