In combination of the merits of Si- and C-based anode materials for lithium-ion batteries (LIBs), we propose and evaluate the potential of novel Si3C as an anode material, which consists of light silicon and carbon atoms and is characterized by a Dirac cone. The adsorption energy for lithium atom is identified to be -2.58 eV, which is large enough to ensure a good lithium adsorption stability during the (de)lithiation process. Our results reveal that the energy barrier for Li diffusion on Si3C is only 0.46 eV, indicative of a fast charge/discharge rate. In addition, Si3C exhibits a semimetallic nature with a great advantage in electrical conductivity. Remarkably, the fully lithiated phase of Si3C is (Li6Si3C)(2), corresponding to a theoretical specific capacity of 1675 mAh/g, almost 4.5 times higher than that of commercial graphite (375 mAh/g). Besides, the low open-circuit voltage (OCV) of (Li6Si3C)(2) is determined to be 0.2 V. These intriguing superiorities endow the Si3C a promising anode material for LIBs.