Uniformly Dispersed Ultrasmall Fe(Co)Ni Alloy Nanoparticles Embedded in Thin-Walled Carbon Nanotubes as High-Performance Anode Materials for Lithium-Ion Battery

Fe-group nanoalloys are one of the most promising next-generation anodes for lithium-ion batteries (LIBs) due to their low cost, high capacity, excellent electrical conductivity, and lithium-storage capability. However, the difficulties in constructing nanostructures and the tendency for alloy nanoparticles to agglomerate limit their practical application. Herein, a hybrid embedding structure with microporosity–mesoporosity is constructed by using thin-walled carbon nanotubes (CNT) as the support. Within this structure, ultrasmall FeNi/CoNi alloy nanoparticles (10 nm) are uniformly embedded into the walls of thin-walled CNTs (FNNT/CNNT). Benefit from this hybrid structure is that the agglomeration of FNNT/CNNT is effectively suppressed, leading to excellent cycling stability and high capacity (596.6 mA h g⁻¹ for FNNT and 557.1 mA h g⁻¹ for CNNT after 300 cycles at 1 A g⁻¹) as anodes for LIBs. In the present method, a reference can be provided for the preparation of metal alloy/carbon nanocomposites.