Ni-Doped SnO₂ Nanoparticles Anchored on Carbon Nanotubes as Anode Materials for Lithium-Ion Batteries

In this work, we synthesized the SnO₂–Ni-carbon nanotube (CNT) (SNC) composite anode material by hydrothermal and ball milling methods. In this ternary composite, Ni-doped SnO₂ is firmly anchored on the few-walled CNTs. Nano-Ni doping prevents the coarsening of Sn, enhances the electron conductivity, and stabilizes the structure during the process of charging and discharging. In addition, the CNTs can effectively buffer the volume change of SnO₂ and improve the conductivity as well as shorten the transport distances of electron and Li⁺. Accordingly, the SNC shows a large reversible capacity of 1245.7 mA h g^–1 after 400 cycles at 0.2 A g^–1. With a capacity of 1078.2 mA h g^–1 after 850 cycles at 1.0 A g^–1, it exhibits a long-term cycling stability. Meanwhile, the capacity can still reach 666.5 mA h g^–1 at 5.0 A g^–1 with excellent rate capability. The performance and stability of this Ni-doped composite are much better than those of SnO₂, implying that SNC is exceedingly prospective as an anode material for lithium-ion batteries.