Simulation, DFT calculation, and experimental investigation of graphene nanoplates@MoS₂@CoS₂ for electrochemically stable Li-S batteries

The practical implementation of Li-S batteries is significantly impeded by pronounced shuttle effects and suboptimal active material utilization rates. However, the development of modified interlayers presents a viable solution to these challenges. In this study, a hydrothermal approach was employed to synthesize two-dimensional hydrophilic GNPs@MoS₂@CoS₂. The resulting GNPs@MoS₂@CoS₂ features a unique hierarchical architecture that not only improves ion mobility but also enhances cell conductivity and facilitates the trapping of polysulfides. Furthermore, the reduction and oxidation peaks observed in cells utilizing the hydrophilic GNPs@MoS₂@CoS₂ were more pronounced compared to those with solely hydrophilic GNPs or MoS₂@CoS₂, indicating superior redox kinetics. The elevated absorption energy associated with GNPs@MoS₂@CoS₂ ensures an improved lithiation process relative to other configurations. Density functional theory (DFT) calculations reveal that the enhanced mobility of Li ions and the effective adsorption of lithium polysulfide chains within GNPs@MoS₂@CoS₂ position it as a promising candidate for the development of high-performance Li-S batteries. The conductive CoS₂ and stable MoS₂ are combined to create an interconnected MoS₂@CoS₂ composite, featuring an electroactive interface that is developed on a Mo substrate. This composite serves as a high-performance electrode material, exhibiting both electrochemical and mechanical stability. The band gap and density of states of MoS₂@CoS₂, as determined by density functional theory simulations, suggest an enhancement in electrical conductivity.