Graphene Modified\nwith Glutarimide for Effective Immobilization\nof Polysulfides in High-Performance Li–S Batteries

Despite its high energy density, lithium–sulfur\n(Li–S)\nbatteries are severely hampered by rapid capacity degradation due\nto “shuttle effect”. In this work, we introduce a polar\norganic molecule glutarimide (GIM) onto the nonpolar graphene (G)\nto form a G–GIM composite as host materials to accommodate\nsulfur and thus assemble the S/G–GIM cathode. First-principle\ncalculations show that GIM can absorb on G via the charge-transfer\neffect among its N atom and CO double bond, while the latter\ncan effectively anchor the otherwise dissolved lithium polysulfides\nto bring them into closer contact with G. Such a configuration is\nalso validated by experimental measurements. Electrochemical tests\non the S/G–GIM cathode exhibit high discharge capacity, better\nrate performance, and longer cycling stability compared to the S/G\ncathode without GIM. Specifically, the S/G–GIM cathode exhibits\nan initial discharge capacity of 1327 mAh·g<sub>s</sub><sup>–1</sup> at a 0.2 C rate and 600 mAh·g<sub>s</sub><sup>–1</sup> after 500 cycles at a 1 C rate. Thus, the introduction of GIM in\nthe sulfur cathode can effectively mitigate the “shuttle effect”\nand improve the utilization of active sulfur. The current study demonstrates\nthat the polar organic molecule additives in carbon host as composite\nsulfur cathode provide an effective and feasible strategy for the\nhigh-energy-density Li–S batteries.