Unlocking Robust Lithium Storage Performance in High 1T-phase Purity MoS2 constructed by Mg Intercalation

Metallic phase molybdenum disulfide (1 T MoS2) is considered one of the most promising anode materials in lithium-ion batteries owing to its outstanding physical and electrochemical properties. However, harsh synthesis conditions and low 1 T phase purity hinder the development of 1 T MoS2. Herein, a novel strategy is designed to construct high 1 T-phase purity MoS2 through the use of magnesium intercalation. XRD, XPS, and density functional theory (DFT) analysis demonstrate the intercalated Mg forming an octahedral coordination with adjacent sulfur atoms in the MoS2 layers. Mg acts as the electron donor, ensuring high 1 T-phase purity which elevates both the conductivity and structural stability of MoS2 anode materials. As a result, Mg-intercalated MoS2 delivers an outstanding rate and cycling performance of 415.7 mAh g-1 at 20 A g-1 after 3000 cycles. Ex-situ XRD and XPS illustrate that the Mg intercalated 1 T MoS2 transforms into amorphous nanograins after the first cycle, which results in outstanding lithium storage stability. This novel and facile strategy for constructing high phase purity 1 T MoS2 unlocks the robust lithium storage ability of 1 T MoS2 and informs its further usage in energy conversion and storage realms beyond lithium-ion batteries.