In one embodiment, the present disclosure provides a sulfur-hydroxylated graphene nanocomposite including at least one graphene sheet with a surface and a plurality of amorphous sulfur nanoparticles homogeneously distributed on the surface. The nanocomposite substantially lacks sulfur microparticles. In other embodiments, the disclosure provides a cathode and a battery containing the nanocomposite. In still another embodiment, the disclosure provides a method of making a sulfur-hydroxylated graphene nanocomposite by exposing a hydroxylated graphene to a sulfur-containing solution for a time sufficient to allow formation of homogeneously distributed sulfur nanoparticles on a surface of the hydroxylated graphene.