Nanostructured MoS with Interlayer Controllably Regulated by Ionic Liquids/Cellulose for High-Capacity and Durable Sodium Storage Properties.

Low intrinsic conductivity and structural instability of MoS as an anode of sodium-ion batteries limit the liberation of its theoretical capacity. Herein, density functional theory simulations for the first time optimize MoS interlayer distance between 0.80 and 1.01 nm for sodium storage. 1-Butyl-3-methyl-imidazolium acetate ([BMIm]Ac) induces cellulose oligomers to intercalate MoS interlayers for achieving controllable distance by changing the mass ratio of cellulose to [BMIm]Ac. Based on these findings, porous carbon loading the interlayer-expanded MoS allowing Na to insert with fast kinetics is synthesized. A carbon layer derived from [BMIm]Ac and cellulose coating the composite prevents the MoS from contacting electrolytes, leading to less sulfur loss for a more reversible specific capacity. Meanwhile, MoS and carbon have a strong interfacial connection through MoN binding, contributing to enhanced structural stability. As expected, while cycling 250 times at 0.1 A g , the MoS -porous carbon composite displays an optimal reversible capacity at 517.79 mAh g as a sodium-ion batteries anode. The cyclic test of 1.0 A g also shows considerable stability (310.74 mAh g after 1000 cycles with 86.26% retentive capacity). This study will open up new possibilities of modifying MoS that serves as an applicable material as sodium-ion battery anode.