The lithium-sulfur battery is a promising energy storage technology due to its high theoretical energy density and low cost, but practical applications are hindered by capacity decay caused by polysulfide shuttle. This study presents a novel strategy to trap polysulfides in the cathode using manganese dioxide (MnO2) nanosheets. The MnO2 nanosheets react with initially formed lithium polysulfides to form surface-bound intermediates, which act as redox shuttles to bind and convert higher polysulfides to insoluble lithium sulfide via disproportionation. The sulfur/MnO2 composite with 75 wt% sulfur exhibits excellent reversible capacity and fade rate over 2,000 cycles. The mechanism is further extended to graphene oxide and suggested to be widely applicable. The research addresses a key challenge in lithium-sulfur battery development and brings the technology closer to practical realization.The lithium-sulfur battery is a promising energy storage technology due to its high theoretical energy density and low cost, but practical applications are hindered by capacity decay caused by polysulfide shuttle. This study presents a novel strategy to trap polysulfides in the cathode using manganese dioxide (MnO2) nanosheets. The MnO2 nanosheets react with initially formed lithium polysulfides to form surface-bound intermediates, which act as redox shuttles to bind and convert higher polysulfides to insoluble lithium sulfide via disproportionation. The sulfur/MnO2 composite with 75 wt% sulfur exhibits excellent reversible capacity and fade rate over 2,000 cycles. The mechanism is further extended to graphene oxide and suggested to be widely applicable. The research addresses a key challenge in lithium-sulfur battery development and brings the technology closer to practical realization.