3D S@MoS₂@reduced graphene oxide aerogels cathode for high-rate lithium-sulfur batteries

Practical application of the lithium-sulfur (Li–S) batteries is still hindered by their capacity decays caused by the shuttling of polysulfides. In this work, 3D MoS₂ nanoporous spheres (MoS₂-NPSs), exposing abundant active edges by decorating on conductive reduced graphene oxide aerogels (rGOA/GA), were fabricated as an S host to construct the S@MoS₂@GA cathodes. An S@MoS₂@GA-0.425 cathode constructed as such delivered an initial capacity of 688 mAh g⁻¹ and arrived at a high discharge capacity of 565 mAh g⁻¹ after 200 cycles at 0.2C; moreover, a reversible capacity of 324 mAh g⁻¹ retained for the electrode after 500 cycles at 1.0C with a slow capacity fading rate of 0.054% per cycle. The improved electrochemical performance can be attributed to the strong interactions of 3D MoS₂@GA with lithium polysulfides intermediates (Li₂S_n where 4 ≤ n ≤ 8), and the fast lithium ion and electron transport channels formed in the cathode for the sulfur redox reaction. More importantly, the MoS₂-NPSs electrocatalyst could chemically adsorb the Li₂S_n to fix soluble ones near the conductive GA surface and also could kinetically accelerate the transformation of Li₂S_n.