Disclosed is a carbon felt impregnated with inorganic particles. The impregnated carbon felt can be used together with sulfur in a cathode of a sodium-sulfur (Na—S) battery. Also disclosed is a method for producing the impregnated carbon felt. According to exemplary embodiments, the problem of the prior art can be solved in which inorganic particles such as alumina particles are not directly adhered to carbon felts, thus necessitating complicated processes. In addition, a slurry including an inorganic binder and alumina particles can be used to directly coat the alumina particles on the surface of a carbon felt, making the production procedure very simple. Furthermore, the use of the carbon felt surface coated with the alumina particles in a Na—S battery increases the wicking of sodium polysulfides, suppresses the accumulation of sulfur as an insulator on the surface of beta-alumina as an electrolyte, and inhibits non-uniform aggregation of sulfur or sodium polysulfides on the carbon felt, so that the concentration polarization of charges can be reduced without a significant increase in the internal resistance of the battery, achieving high utilization efficiency of sulfur as a reactant.