Impact of Si⁴⁺ Ions Doping on the Electrochemical Cycling Performance of NiTiO₃ as Anodes for Li-Ion Batteries

Pristine and Si⁴⁺ doped NiTiO₃ are successfully synthesized by molten salt method and electrochemically characterized for its use as an anode material for Li-ion batteries. The X-ray diffraction (XRD) results enumerates that the lattice parameter and the cell volume decreases upon the addition of Si⁴⁺ due to its smaller ionic radius. The presence of Si⁴⁺ in NiTiO₃ structure was also confirmed using FTIR analysis, which showed the stretching vibrations of Si—O at ∼1008 cm⁻¹. The SEM images reveal that the NiTiO₃ particles are in micrometer range and the size of the particle is found to be decrease after Si⁴⁺ addition. The electrical studies infers an enhancement in the conductivity from 4.4×10⁻⁷ S·cm⁻¹ to 1.7×10⁻⁶ S·cm⁻¹ on dopant addition. The initial discharge capacity of NiTiO₃ is found to be 1257 mA h g⁻¹ and there is a capacity fading on consecutive cycles. NiTi_0.9Si_0.1O₃ enhances the cyclic performances and a constant capacity around 400 mA h g⁻¹ is maintained, a very good reversibility with almost 100% efficiency is observed elucidating the fact that almost all the Li ions intercalated are successfully de-intercalated during the discharge process.