Dual-Functional Interlayer Based on Radially Oriented Ultrathin MoS₂ Nanosheets for High-Performance Lithium–Sulfur Batteries

The polysulfide shuttle is a major challenge for practical application of lithium–sulfur (Li–S) batteries. To solve this issue, a thin layer (3 μm) of radially oriented 3D MoS2 nanospheres (3D MoS2) constructed by 2D MoS2 nanosheets is developed as an interlayer coating overlaid on the sulfur cathode, which can simultaneously prevent polysulfide migration and facilitate Li+ diffusion. The trapping and catalytic conversion of polysulfides would benefit from the abundant active edge sites and the large contact surface in the well-preserved MoS2 nanosheets. Meanwhile, fast Li+ diffusion can be realized by the expanded (002) interlayer of the MoS2 nanosheets along with the sufficient electrolyte wettability due to the open 3D structure. Thus, the Li–S batteries with a 3D MoS2 interlayer and the pure sulfur cathode exhibit high specific capacity, excellent cycling stability (62.5% capacity retention with a 0.06% capacity decay per cycle and >99% Coulombic efficiency over 600 cycles), and satisfactory areal capacities of 2.92–3.96 mAh cm–2 at different currents under increased sulfur loading. Furthermore, it is feasible to incorporate the slurry cast interlayer into the existing electrode fabrication, which sheds light on constructing advanced interlayers for commercially viable Li–S batteries.