context: For full cell testing, sulfur–carbon composite cathodes were used. It is well known that S, lithium disulfide and other reaction intermediates have poor electronic conductivity. To improve this, S nanoparticles were impregnated into a nitrogen doped carbon matrix (from now on labelled ‘S/NC’); a detailed account on the synthesis of the cathode was given in our previous report. The carbon composite matrix with good electronic conductivity and a high surface area (700 m2 g−1) contained graphene and multiwall carbon nanotubes in an equal weight ratio. The morphology of the cathode material is illustrated in the SEM image shown in Fig. S4.† Further, thermo-gravimetric analysis (TGA) shows a S loading of ∼55 wt% in the S/NC cathode (Fig. S5, ESI†).
answer: sulfur–carbon composite