MoSe2 nanosheets as a functional host for lithium-sulfur batteries

Abstract Lithium-sulfur batteries (LSBs) hold great potential for large-scale electrochemical energy storage applications. Currently, the shuttle of soluble lithium polysulfide (LiPSs) intermediates with sluggish conversion kinetics and random deposition of Li2S have severely degraded the capacity, rate and cycling performances of LSBs, preventing their practical applications. In this work, ultrathin MoSe2 nanosheets with active edge sites were successfully grown on both internal and external surfaces of hollow carbon spheres with mesoporous walls (MCHS). The resulting MoSe2@MCHS composite acted as a novel functional reservoir for LiPSs with high chemical affinity and effectively mediated their fast redox conversion during charge/discharge as elucidated by experimental observations and first-principles density functional theory (DFT) calculations. The as-fabricated Li-S cells delivered high capacity, superior rate and excellent cyclability. The current work presents new insights on the delicate design and fabrication of novel functional composite electrode materials for rechargeable batteries with emerging applications.