Li-S) batteries are considered as promising next-generation energy storage systems due to their high theoretical energy density (2600 Wh kg −1 ) and high specific capacity (1675 mAh g −1 ) that far exceed the state-of-the-art lithium-ion batteries. [3][4][5] In addition, the environmental friendliness and cost-effective nature of sulfur make Li-S batteries a strong competitive advantage in the market. [6] In spite of these advantages, the commercialization of Li-S batteries is still hindered by the rapid capacity decay, poor cycle stability and low coulombic efficiency due to the following problems. 1) The poor conductivity of sulfur (≈10 −30 S cm −1 ) and its discharge product Li 2 S (≈10 −13 S cm −1 ) lead to low utilization of active material. [6,7] 2) Due to the different densities of S (2.03 g cm −3 ) and Li 2 S (1.66 g cm −3 ), severe volume expansion/contraction (≈80%) leads to the collapse of the cathode structure. [8,9] 3) The notorious "shuttle effect" caused by the soluble lithium polysulfides (Li 2 S x , 4 ≤ x ≤ 8), that is, the intermediates generated during the discharge process easily dissolve in the ether-based electrolyte and diffuse to the lithium anode, leads to the corrosion of lithium metal and rapid fading of capacity. [8,10,11] 4) In the process of repeated lithium plating/stripping, uncontrollable lithium dendrites form on the anode, causing short circuit and safety problems. [1,12] In order to address these issues, great efforts have been devoted in the past decade to construct various multifunctional sulfur-based composite cathodes using diverse host materials, such as carbon materials, [13,14] polar materials, [15][16][17] conductive polymers, [18] etc.. Based on this strategy, great progress has been made in improving the performance of Li-S batteries. However, the low actual content of active material and the cumbersome preparation process of the composites usually sacrifice the energy density and increase the cost, which is very unfavorable to the actual requirements of industrial production. [19,20] In contrast to the sulfur cathode architectures, designing functional separators is a simple and effective approach to inhibit the shuttle effect and improve the electrochemical performance of Li-S batteries. In this regard, various carbonaceous materials, such as carbon nanotubes, [21] graphene, [22] and hierarchical porous carbon [23] have been widely used to functionalize separators. However, the weak van der Waals interaction between The notorious shuttle effect and sluggish conversion of polysulfides seriously hinder the practical application of Lithium-sulfur (Li-S) batteries. In this study, a novel architecture of MoS 2 /MoO 3 heterostructure uniformly distributed on carbon nanotubes (MoS 2 /MoO 3 @CNT) is designed and introduced into Li-S batteries via decorating commercial separator to regulate the redox reactions of polysulfides. Systematic experiments and theoretical calculations showed that the heterostructure not only provides sufficient surface affinity to capture polysulfi...

SnS 2 -based materials have attracted considerable attention in energy storage and conversion owing to their high lithium activity and theoretical capacity. However, the practical application is severely limited by the low coulombic efficiency and short cycle life due to irreversible side reactions, low conductivity, and serious pulverization in the discharge/charge process. In this study, sheet-like stacking SnS 2 /reduced graphene oxide (rGO) heterostructures were developed using a facile solvothermal method. It was found that the composites between SnS 2 nanoplates and rGO nanosheets are closely coupled through van der Waals interactions, providing efficient electron/ion paths to ensure high electrical conductivity and sufficient buffer space to alleviate volume expansion. Therefore, the SnS 2 /rGO heterostructure anode can obtain a high capacity of 840 mA h g −1 after 120 cycles at a current density of 200 mA g −1 and maintain a capacity of 450 mA h g −1 after 1000 cycles at 1000 mA g −1 . In situ X-ray diffraction tests showed that SnS 2 /rGO undergoes typical initial intercalation, conversion, and subsequent alloying reactions during the first discharge, and most of the reactions are dealloying/alloying in the subsequent cycles. The galvanostatic intermittent titration technique showed that the diffusion of lithium ions in the SnS 2 /rGO heterostructures is faster in the intercalation and conversion reactions than in the alloying reactions. These observations help to clarify the reaction mechanism and ion diffusion behavior in the SnS 2 anode materials, thus providing valuable insights for improving the energy efficiency of lithium-ion batteries.