Interfaces-dominated Li2S nucleation behavior enabled by heterostructure catalyst for fast kinetics Li-S batteries

Lithium-sulfur batteries (LSBs) have gained wide attention in the past decades for its high energy density and low cost. However, LSBs practical application is hindered by the severe shuttling of soluble intermediate lithium polysulfides (LiPSs), and the uncontrollable deposition of insulating Li2S, which limits the active species utilization and decelerates the redox kinetics. In this study, MoO2/α-MoC nanocomposite was investigated as a multifunctional electrocatalyst to address above problems. Not only does such electrocatalyst immobilizes LiPSs on its surface but also facilitate the subsequent conversion reaction, further enable the heterogeneous Li2S nucleation and induce three-dimensional precipitation of Li2S. MoO2/α-MoC-containing LSBs exhibit excellent rate performance, promising cycling stability, and a high specific capacity of 1177 mAh g−1 at 0.2 C and 695 mAh g−1 at 3 C with a low-capacity deterioration. Good cyclic stability was achieved at 0.5 C even with a high sulfur loading of 5 mg cm−2 and a low E/S ratio of 6–7 μL mg−1 by employing a MoO2/α-MoC interlayer.