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

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