Comparative Study of Mechanically Milled MoS₂ and MoSe₂ in Graphite Matrix as Anode Materials for High-Performance Lithium-Ion Batteries.

Nanocomposites of MoS2/graphite and MoSe2/graphite were formed from two-dimensional materials (MoS2 and MoSe2) and graphite using a one-step ball-milling method (high energy mechanical milling, HEMM). As anode materials for lithium-ion batteries (LIBs), these nanocomposites showed higher specific capacity and greater stability during long cyclic operation compared to their pure counterparts (MoS2 and MoSe2). X-ray diffraction and transmission electron microscopy revealed that graphite nanoflakes were effectively exfoliated and covered MoS2 or MoSe2 layers to form homogeneous nanostructures via HEMM. As a result, the electrochemical performances of both MoS2/graphite and MoSe2/graphite were excellent; the specific capacities were as high as 684.8 (MoS2/graphite) and 787.3 mAh g-1 (MoSe2/graphite) after 100 cycles. Also, when compared with MoS2/graphite, the MoSe2/graphite nanocomposite showed higher specific capacity and better rate capability performance due to larger interlayer spacing, leading to fast and facile movement of Liions. Overall, we demonstrate that homogeneous nanocomposites between similar layered materials (MoS2, MoSe2 and graphite) can be easily synthesized via one-step HEMM, which can be used as excellent anode materials for LIBs.