Tubular-like Nanocomposites with Embedded CuS-MoS Crystalline-Amorphous Heterostructure in N-Doped Carbon as Li-Ion Batteries Anode toward Ultralong Cycling Stability.

Transition metal sulfides (TMSs) show the potential to be competitive candidates as next-generation anode materials for Li-ion batteries (LIBs) due to their high theoretical specific capacity. However, sluggish ionic/electronic transportation and huge volume change upon lithiation/delithiation remain major challenges in developing practical TMS anodes. We rationally combine structural design and interface engineering to fabricate a tubular-like nanocomposite with embedded crystalline CuS5 nanoparticles and amorphous MoS in a carbon matrix (C/CuS-MoS NTs). On the one hand, the hybrid integrated the advantages of 1D hollow nanostructures and carbonaceous materials, whose high surface-to-volume ratios, inner void, flexibility, and high electronic conductivity not only enhance ion/electron transfer kinetics but also effectively buffer the volume changes of metal sulfides during charge/discharge. On the other hand, the formation of crystalline-amorphous heterostructures between CuS and MoS could further boost charge transfer due to an induced built-in electric field at the interface and the presence of a long-range disorder phase. In addition, amorphous MoS offers an extra elastic buffer layer to release the fracture risk of CuS crystalline nanoparticles during repetitive electrochemical reactions. Benefiting from the above synergistic effect, the C/CuS-MoS electrode as an LIB anode in an ether-based electrolyte achieves a high-rate capability (445 mAh g at 6 A g) and superior ultralong-term cycling stability, which delivers an initial discharge capacity of 561 mAh g at 2 A g and its retention capacity after 3600 cycles (376 mAh g) remains higher than that of commercial graphite (372 mAh g).