(352h) Free-Standing Bimetallic Sulfide@Carbon Nanofiber Networks As Lithium-Ion Battery Anodes

Anode materials play a crucial role in the overall electrochemical performance of lithium-ion batteries (LIBs). In this work we use electrospinning, a straight-forward, scalable, and low-cost technique, to embed nickel cobalt sulfide nanoparticles into carbon nanofiber networks. After obtaining fresh nanofibers via electrospinning, the fresh fiber mat is simultaneously carbonized and sulfurized under the nitrogen atmosphere at 700°C for 1 hour, where we obtained the free-standingnonwoven carbon nanofiber networks embedded with metal sulfide nanoparticles subsequently. The as-prepared materials are highly stable with numerous pores among the fiber networks, allowing for fast electrolyte penetration. When tested as the anode, the materials exhibit high reversible capacity, superior capability, and excellent rate performance. These excellent performances can be attributed to the fact that the nonwoven 3D fiber networks, not only do they provide more active sites but also are highly resistant to volume expansion. Additionally, the synergistic effect of two metal sulfides enhances the performance of lithium-ion storage. Furthermore, this free-standing and binder-free electrode also avoids tedious slurry making steps and eliminates uncontrolled structure formation, low porosity, and undesirable interfaces caused by involving binder and the extra substrate. Ultimately, we reveal a facile method to design LIBs anode materials with excellent performance.