Novel 2D Layered Molybdenum Ditelluride Encapsulated in Few-Layer Graphene as High-Performance Anode for Lithium-Ion...

Molybdenum ditelluride nanosheets encapsulated in few-layer graphene (MoTe₂ /FLG) are synthesized by a simple heating method using Te and Mo powder and subsequent ball milling with graphite. The as-prepared MoTe₂ /FLG nanocomposites as anode materials for lithium-ion batteries exhibit excellent electrochemical performance with a highly reversible capacity of 596.5 mAh g^-1 at 100 mA g^-1 , a high rate capability (334.5 mAh g^-1 at 2 A g^-1 ), and superior cycling stability (capacity retention of 99.5% over 400 cycles at 0.5 A g^-1 ). Ex situ X-ray diffraction and transmission electron microscopy are used to explore the lithium storage mechanism of MoTe₂ . Moreover, the electrochemical performance of a MoTe₂ /FLG//0.35Li₂ MnO₃ ·0.65LiMn_0.5 Ni_0.5 O₂ full cell is investigated, which displays a reversible capacity of 499 mAh g^-1 (based on the MoTe₂ /FLG mass) at 100 mA g^-1 and a capacity retention of 78% over 50 cycles, suggesting the promising application of MoTe₂ /FLG for lithium-ion storage. First-principles calculations exhibit that the lowest diffusion barrier (0.18 eV) for lithium ions along pathway III in the MoTe₂ layered structure is beneficial for improving the Li intercalation/deintercalation property.