2D interspace confined growth of ultrathin MoS₂-intercalated graphite hetero-layers for high-rate Li/K storage

Herein, a two-dimensional (2D) interspace-confined synthetic strategy is developed for producing MoS₂-intercalated graphite (G-MoS₂) hetero-layers composite through sulfuring the pre-synthesized stage-1 MoCl₅-graphite intercalation compound (MoCl₅-GIC). The in situ grown MoS₂ nanosheets (3-7 layers) are evenly encapsulated in graphite layers with intimate interface thus forming layer-by-layer MoS₂-intercalated graphite composite. In this structure, the unique merits of MoS₂ and graphite components are integrated, such as high capacity contribution of MoS₂ and the flexibility of graphite layers. Besides, the tight interfacial interaction between hetero-layers optimizes the potential of conductive graphite layers as matrix for MoS₂. As a result, the G-MoS₂ exhibits a high reversible Li⁺ storage of 344 mAh·g⁻¹ even at 10 A·g⁻¹ and a capacity of 539.9 mAh·g⁻¹ after 1,500 cycles at 5 A·g⁻¹. As for potassium ion battery, G-MoS₂ delivers a reversible capacity of 377.0 mAh·g⁻¹ at 0.1 A·g⁻¹ and 141.2 mAh·g⁻¹ even at 2 A·g⁻¹. Detailed experiments and density functional theory calculation demonstrate the existence of hetero-layers enhances the diffusion rates of Li⁺ and K⁺. This graphite interspace-confined synthetic methodology would provide new ideas for preparing function-integrated materials in energy storage and conversion, catalysis or other fields.