Mo‐O‐C Between MoS₂ and Graphene Toward Accelerated Polysulfide Catalytic Conversion for Advanced Lithium‐Sulfur Batteries

Abstract

MoS 2 /C composites constructed with van der Waals forces have been extensively applied in lithium–sulfur (Li–S) batteries. However, the catalytic conversion effect on polysulfides is limited because the weak electronic interactions between the composite interfaces cannot fundamentally improve the intrinsic electronic conductivity of MoS 2 . Herein, density functional theory calculations reveal that the MoS 2 and nitrogen‐doped carbon composite with an Mo–O–C bond can promote the catalytic conversion of polysulfides with a Gibbs free energy of only 0.19 eV and a low dissociation energy barrier of 0.48 eV, owing to the strong covalent coupling effect on the heterogeneous interface. Guided by theoretical calculations, a robust MoS 2 strongly coupled with a 3D carbon matrix composed of nitrogen‐doped reduced graphene oxide and carbonized melamine foam is designed and constructed as a multifunctional coating layer for lithium–sulfur batteries. As a result, excellent electrochemical performance is achieved for Li–S batteries, with a capacity of 615 mAh g –1 at 5 C, an areal capacity of 6.11 mAh cm –2 , and a low self‐discharge of only 8.6% by resting for five days at 0.5 C. This study opens a new avenue for designing 2D material composites toward promoted catalytic conversion of polysulfides.

Decoration of defective graphene with MoS2enabling enhanced anchoring and catalytic conversion of polysulfides for lithium–sulfur batteries: a first-principles study

“…6(a). The calculation route of the sulfur reduction reaction refers to the previous report, 50–54 and our calculation results are basically consistent with the trend in these references: except that the last reduction step (Li 2 S 2 → Li 2 S) is an endothermic process, the rest of the elementary steps are exothermic, implying that the last reduction step is the rate-limiting step of the overall SRR. The endothermic reaction of the Li 2 S 2 → Li 2 S step is attributed to the intractable solid-state reaction, which is basically consistent with those reported in other literature reports.…”

Hollow Co3S4 Nanocubes Interconnected with Carbon Nanotubes as Nanoreactors to Accelerate Polysulfide Conversion for High-Performance Lithium–Sulfur Batteries

“…To visually inspect the restraining shuttle effect of Co 3 S 4 /CNTs and CNTs, the Li 2 S 6 adsorption measure was tested as shown in Figure a . The dark yellow color of the Li 2 S 6 solution became transparent after adding Co 3 S 4 /CNTs and immersing for 12 h, while the color of the Li 2 S 6 solution containing CNTs faded only a little.…”

Understanding the Catalytic Kinetics of Polysulfide Redox Reactions on Transition Metal Compounds in Li–S Batteries

“…99 Moreover, metal sulfides generally exhibit better electrical conductivity than metal oxides, which is advantageous for the electrochemistry conversion in sulfide electrodes. Therefore, some typical metal sulfides, such as FeS, 100 VS, 101 and MoS 2 , 102 that are combined with carbon materials have attracted many discussions around Li−S batteries. Table 2 exhibits the electrochemical performance of metal sulfides as a sulfur host/separator modifier in Li−S batteries.…”