Carbon-nickel core-shell nanofibers decorated with bimetallic nickel-gallium chalcogenide nanosheets as flexible, binder-free lithium-ion-battery anodes

We fabricated ultrathin nanosheets of bimetallic chalcogenides (NiGa₂S₄) using a hydrothermal process, which significantly reduced the number of Li⁺ diffusion pathways and promoted rapid electron transport. Flexible carbon nanofibers (CNFs) were prepared by electrospinning and post-annealing. These CNFs were electroplated with nickel and decorated with gallium, which has a relatively high theoretical capacity and low volume-expansion rate during lithiation. The gallium concentration was optimized to obtain the thinnest and most uniform NiGa₂S₄ nanosheets. The optimal anode exhibited a reversible specific capacity of 1349 mAh·g⁻¹ at a current density of 62.5 mA·g⁻¹ in the first cycle. Furthermore, the NiGa₂S₄ anode was used to power a light-emitting-diode under severe bending conditions, demonstrating its superior mechanical durability.