Insight into the Capacitive Performance of Sulfur-Doped Nanoporous Carbons Modified by Addition of Graphene Phase

The composites of nanoporous carbon and graphene were prepared by carbonization of mixed sulfonate-based polymers and graphite oxide. Addition of the graphene phase modified the texture and chemistry of the final products. The materials show high electrochemical capacity in spite of the relatively low surface area. The good performance is linked to the presence of sulfur in the small pores, which brings a positive charge on carbon atoms and thus increases the attraction to anions, to the sulfones, sulfoxides and quinones in larger pores, which undergo Faradaic reactions, and to the balanced content of oxygen groups, which provides the wettability.