Layer-Spacing-Enlarged MoS2 Superstructural Nanotubes with Further Enhanced Catalysis and Immobilization for Li-S Batteries.

A layer-spacing-enlarged MoS2 nanotube (LE-MoS2) consisting of hierarchical superstructural nanosheets (-MoS2-carbon layer-MoS2-) was fabricated and served as the sulfur host. The (002) lattice plane of LE-MoS2 is greatly expanded to 1.04 nm and 67.7% higher than that of the conventional 2H-MoS2. Benefitting from the layer-spacing-enlarged hierarchical superstructure of LE-MoS2, the catalytic effect on the S(s)-Li2Sx (soluble, x > 6)-Li2Sy (soluble, y > 2)-Li2S(s) phase transformation kinetics and immobilizing effect on the soluble Li2Sy in Li-S batteries are both further enhanced and demonstrated by in situ X-ray adsorption near-edge structure spectroscopy and first-principles calculations. The formation of hierarchical superstructural nanosheets was carefully investigated by customized synchrotron vacuum ultraviolet photoionization mass spectrometry.