▎ 摘　　要

Although lithium-polysulfur (Li-polyS) batteries employing organic polymeric sulfur as a cathode material outperform the lithium-sulfur (Li-S) battery system, the relatively low sulfur loading (<2 mg cm(-2)) in the current Li-polyS batteries compromises the areal capacity, constraining their practicality. We present here a new cathode active material (a covalently grafted polysulfur-graphene nanocomposite (polySGN)) for ultrahigh loading Li-polyS batteries. The new cathode active material polySGN offers several advantages: (i) the well-dispersed graphene sheets offer highly electrically conductive pathways for electrons to travel within the polySGN matrix; (ii) the intermediate organosulfide moieties alleviate irreversible sulfide deposition on electrodes; and (iii) the in situ formed coating layer on the cathode-side surface of the polymeric separator further reduces polysulfide migration. The Li-polyS batteries employing polySGN as the cathode active material accomplish the highest sulfur loading (up to 10.5 mg cm(-2)) and the highest areal capacity (,(-)similar to 12 mA h cm(-2)) reported thus far in the literature.