Ultrathin MoS₂ with expanded interlayers supported on hierarchical polypyrrole-derived amorphous N-doped carbon tubular structures for high-performance Li/Na-ion batteries

Layered molybdenum disulfide (MoS₂) has received much attention as one of the most promising energy-storage and conversion materials for Li/Na ion batteries. Here, a simple and effective approach is proposed for the rational design and preparation of hierarchical three-d imensional (3D) amorphous N-doped carbon nanotube@MoS₂ nanosheets (3D-ANCNT@MoS₂) via a simple hydrothermal method, followed by an annealing process. With such a unique nanoarchitecture, ultrathin MoS₂ nanosheets grown on the external surfaces of polypyrrole-derived ANCNTs are assembled to form a hierarchical 3D nanoarchitecture, where the adopted ANCNTs serve not only as the template and continuous conductive matrix, but can also prevent MoS₂ from aggregating and restacking, and help to buffer the volumetric expansion of MoS₂ during cycling. More importantly, when evaluated as an anode material for lithium-ion batteries, the 3D-ANCNT@MoS₂ composite exhibits excellent cycling stability, superior rate performance, and reversible specific capacity as high as 893.4 mAh·g^-1 at 0.2 A·g^-1 after 200 cycles in a half battery, and 669.4 mAh·g^-1 at 0.2 A·g^-1 after 100 cycles in the 3D-ANCNT@MoS₂//LiCoO₂ full battery. With respect to sodium-ion batteries, the outstanding reversible capacity, excellent rate behavior, and good cycling performance of 3D-ANCNT@MoS₂ composites are also achieved.