N-Doping Induced Lattice Expansion of 1D Template Confined Ultrathin MoS2 Sheets to Significantly Enhance Lithium Polysulfides Redox Kinetics for Li-S Battery

摘要

Preparing MoS2-based materials with reasonable structure and catalytic activity to enhance the sluggish kinetics of lithium polysulfides (LiPSs) conversion is of great significance for Li-S batteries (LSBs) but still remain a challenge. Hence, hollow nanotubes composed of N-doped ultrathin MoS2 nanosheets (N-MoS2 NHTs) are fabricated as efficient S hosts for LSBs by using CdS nanorods as a sacrifice template. Characterization and theoretical results show that the template effectively inhibits the excessive growth of MoS2 sheets, and N doping expands the interlayer spacing and modulates the electronic structure, thus accelerating the mass/electron transfer and enhancing the LiPSs adsorption and transformation. Benefiting from the merits, the N-MoS2 NHTs@S cathode exhibits an excellent initial capacity of 887.8 mAh g(-1) and stable cycling performances with capacity fading of only 0.0436% per cycle at 1.0 C (500 cycles). Moreover, even at high S loading that of 7.5 mg cm(-2), the N-MoS2 NHTs@S cathode also presents initial excellent areal capacity of 7.80 mAh cm(-2) at 0.2 C. This study offers feasible guidance for designing advanced MoS2-based cathode materials in LSBs.

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