Enhancements of surface functional groups and degree of graphitization in gamma irradiated activated carbon as an electrode material

Abstract

Enhancements of oxygen-containing groups on the surface of activated carbons (ACs) and the degree of graphitization in their structures allow a potential solution for the development of the cathode materials in Lithium Sulfur Batteries (LSBs). Despite the two factors having been researched considerably, the most applicable electrochemical performances and development method of the materials have not been reached. Here the chemical properties of a commercial AC in terms of surface functional groups and degree of graphitization were successfully improved by gamma irradiation with dose and medium variations. The number of oxygen-containing groups on the AC surface and the degree of graphitization in its structure were both found to increase after gamma irradiation, depending strongly upon the irradiation dose and medium type. The best electrochemical performance of 900 mAh/g capacity given by the AC irradiated in water medium under the experimental conditions suggested a larger correlation with the number of oxygen-containing groups than that with the degree of graphitization, which was found to be maximized in air.