MnO(2)/rGO/CNTs Framework as a Sulfur Host for High-Performance Li-S Batteries

Lithium-sulfur batteries are very promising next-generation energy storage batteries due to their high theoretical specific capacity. However, the shuttle effect of lithium-sulfur batteries is one of the important bottlenecks that limits its rapid development. Herein, physical and chemical dual adsorption of lithium polysulfides are achieved by designing a novel framework structure consisting of MnO(2), reduced graphene oxide (rGO), and carbon nanotubes (CNTs). The framework-structure composite of MnO(2)/rGO/CNTs is prepared by a simple hydrothermal method. The framework exhibits a uniform and abundant mesoporous structure (concentrating in ~12 nm). MnO(2) is an α phase structure and the α-MnO(2) also has a significant effect on the adsorption of lithium polysulfides. The rGO and CNTs provide a good physical adsorption interaction and good electronic conductivity for the dissolved polysulfides. As a result, the MnO(2)/rGO/CNTs/S cathode delivered a high initial capacity of 1201 mAh g(−1) at 0.2 C. The average capacities were 916 mAh g(−1), 736 mAh g(−1), and 547 mAh g(−1) at the current densities of 0.5 C, 1 C, and 2 C, respectively. In addition, when tested at 0.5 C, the MnO(2)/rGO/CNTs/S exhibited a high initial capacity of 1010 mAh g(−1) and achieved 780 mAh g(−1) after 200 cycles, with a low capacity decay rate of 0.11% per cycle. This framework-structure composite provides a simple way to improve the electrochemical performance of Li-S batteries.