Synergistic polysulfide regulation by CeO2/N-doped graphene composites for durable lithium–sulfur batteries

Lithium–sulfur (Li–S) batteries are promising next-generation energy storage systems due to their high theoretical capacity and low cost, but they suffer from the insulating nature of sulfur, significant volume change, and the polysulfide shuttle effect. To address these challenges, we designed and synthesized a CeO 2 -decorated N-doped reduced graphene oxide (N-rGO/CeO 2 ) composite as a sulfur host. The N-rGO framework ensures high electrical conductivity and offers abundant active sites for sulfur species, while the CeO 2 nanoparticles, with their Ce 4+ /Ce 3+ redox couple, effectively immobilize polysulfides and catalyze their conversion. This unique structure couples a highly conductive N-rGO network with uniformly dispersed nanoparticles, resulting in a synergistic system that integrates physical confinement, strong chemisorption, and efficient electrocatalysis. N-rGO/CeO 2 /S cathode delivers a high initial discharge capacity of 1330.9 mAh g −1  at 0.1C and maintains 730.0 mAh g −1 after 100 cycles at 0.2C. Remarkably, it exhibits outstanding long-term cyclability, retaining capacities of 432.4 and 327.0 mAh g −1 after 1000 cycles at 1 C and 3 C, respectively, corresponding to an ultralow capacity decay rate of only 0.024% per cycle at 1 C. This work highlights the effectiveness of the N-rGO/CeO 2 composite as a multifunctional host for high-performance Li–S batteries.