This article presents a novel chemical strategy for trapping polysulfides in lithium-sulfur (Li-S) batteries, which significantly improves their performance. The method involves using manganese dioxide (MnO₂) nanosheets as a host material that reacts with lithium polysulfides (LiPSs) to form surface-bound intermediates. These intermediates act as redox shuttles to convert higher polysulfides into insoluble lithium sulfide (Li₂S) through disproportionation. The resulting sulfur/MnO₂ composite with 75 wt% sulfur exhibits a high reversible capacity of 1,300 mA h g⁻¹ at moderate rates and a fade rate of 0.036% per cycle over 2,000 cycles, which is among the best reported. The mechanism is also applicable to graphene oxide, suggesting broader utility. The Li-S battery is attractive due to its high theoretical energy density and low cost, but practical applications are hindered by the polysulfide shuttle effect. This study addresses this issue by using MnO₂ nanosheets to trap polysulfides, preventing their dissolution and enhancing cycle life. The MnO₂ nanosheets are synthesized by reducing graphene oxide (GO) with KMnO₄. The sulfur is then uniformly dispersed onto the nanosheets through melt diffusion. Electrochemical tests show that the 75S/MnO₂ composite has excellent performance, with a capacity of 1,300 mA h g⁻¹ at C/20 and 800 mA h g⁻¹ at 1C after 200 cycles. In-situ studies using an optically transparent Li-S cell demonstrate that the MnO₂ nanosheets effectively trap polysulfides, as evidenced by the color change of the electrolyte. XPS analysis confirms the formation of thiosulfate species on the MnO₂ surface, which facilitates the conversion of polysulfides to Li₂S. The study also shows that the MnO₂ nanosheets can interact with LiPSs to form thiosulfate and polythionate complexes, which help in controlling the redox reactions and reducing the polysulfide shuttle. The mechanism is further validated by comparing the performance of MnO₂ with other sulfur hosts like GO and graphene. The results indicate that the MnO₂ nanosheets provide an effective interface for controlling polysulfide dissolution and deposition, leading to high cycle stability and capacity retention. The research highlights a new, efficient mechanism for polysulfide mediation in Li-S batteries, which could lead to more practical applications of this technology. The study demonstrates that the MnO₂ nanosheet host can spatially control the deposition of Li₂S and sulfur, enhancing the overall stability and performance of the battery. The findings suggest that this approach could be widely applicable to other sulfur host materials, improving the cycling behavior of Li-S batteries.This article presents a novel chemical strategy for trapping polysulfides in lithium-sulfur (Li-S) batteries, which significantly improves their performance. The method involves using manganese dioxide (MnO₂) nanosheets as a host material that reacts with lithium polysulfides (LiPSs) to form surface-bound intermediates. These intermediates act as redox shuttles to convert higher polysulfides into insoluble lithium sulfide (Li₂S) through disproportionation. The resulting sulfur/MnO₂ composite with 75 wt% sulfur exhibits a high reversible capacity of 1,300 mA h g⁻¹ at moderate rates and a fade rate of 0.036% per cycle over 2,000 cycles, which is among the best reported. The mechanism is also applicable to graphene oxide, suggesting broader utility. The Li-S battery is attractive due to its high theoretical energy density and low cost, but practical applications are hindered by the polysulfide shuttle effect. This study addresses this issue by using MnO₂ nanosheets to trap polysulfides, preventing their dissolution and enhancing cycle life. The MnO₂ nanosheets are synthesized by reducing graphene oxide (GO) with KMnO₄. The sulfur is then uniformly dispersed onto the nanosheets through melt diffusion. Electrochemical tests show that the 75S/MnO₂ composite has excellent performance, with a capacity of 1,300 mA h g⁻¹ at C/20 and 800 mA h g⁻¹ at 1C after 200 cycles. In-situ studies using an optically transparent Li-S cell demonstrate that the MnO₂ nanosheets effectively trap polysulfides, as evidenced by the color change of the electrolyte. XPS analysis confirms the formation of thiosulfate species on the MnO₂ surface, which facilitates the conversion of polysulfides to Li₂S. The study also shows that the MnO₂ nanosheets can interact with LiPSs to form thiosulfate and polythionate complexes, which help in controlling the redox reactions and reducing the polysulfide shuttle. The mechanism is further validated by comparing the performance of MnO₂ with other sulfur hosts like GO and graphene. The results indicate that the MnO₂ nanosheets provide an effective interface for controlling polysulfide dissolution and deposition, leading to high cycle stability and capacity retention. The research highlights a new, efficient mechanism for polysulfide mediation in Li-S batteries, which could lead to more practical applications of this technology. The study demonstrates that the MnO₂ nanosheet host can spatially control the deposition of Li₂S and sulfur, enhancing the overall stability and performance of the battery. The findings suggest that this approach could be widely applicable to other sulfur host materials, improving the cycling behavior of Li-S batteries.