Multifunctional ionic liquid-assisted interfacial engineering towards ZnS nanodots with ultrastable high-rate lithium storage performance.

In this article, a new zinc-containing ionic liquid (IL) [HMMIm]2[ZnCl4] (HMMIm = 1-hexyl-2,3-dimethyl-imidazolium) is designed, which acts as a multifunctional source for the interfacial engineering of ZnS nanodots (NDs). Given the electrostatic interaction driven by the imidazolium cation, the steric effect of the alkyl chain, and the in-situ released Zn ion from the IL, the [HMMIm]2[ZnCl4] has shown great advantages in controlling the formation of ZnS NDs. Based on this strategy, a nanocomposite consisting of homodispersed ZnS NDs anchored on sulfur/nitrogen dual-doped reduced graphene oxide (ZnS-NDs@SNG) is fabricated. When evaluated as an anode material for lithium-ion batteries (LIBs), the nanocomposite delivers high reversible specific capacity, excellent high-rate performance, and superior cycling life. Particularly, a discharge capacity of 648.1 mAh g−1 can be reached at a high current density (10.0 A g−1) over 5000 cycles. Benefitting from the multifunctional IL and the simple synthesis protocol, the IL-assisted interfacial engineering strategy will enable a new avenue for the controllable synthesis of metal-sulfide-based anode materials.