Atomic-Level Design of Doped TiO ₂ for Enhanced Lithium Storage: A Density Functional Theory Approach

This study employed first-principles DFT and analyzed the effect of doping anatase TiO 2 with transition metals, particularly Molybdenum (Mo), Niobium (Nb), and Vanadium (V), on the material’s performance as an anode for a lithium-ion battery. The formation energies are all negative, suggesting the doped systems are thermodynamically stable in most instances. Although the host tetragonal anatase structure remains unchanged, structural analysis reveals local distortions concentrated around the dopant sites. Electronic DOS/PDOS analysis indicates that the d-states caused by doping lie relatively close to the Fermi level. This seems to enhance electrical conductivity and reduce the bandgap; hence, we find this observation particularly interesting. Besides, lithium adsorption is found to be quite promising, with E ads ranging from −1.6 to −2.3 eV. Additionally, NEB calculations show that the barriers to diffusion are smaller than those with pure TiO 2 . However, theoretically, the specific capacities were significantly improved to 559.1, 590.4, and 620.1 mAh g −1 for V-, Nb-, and Mo-doped TiO 2 , respectively. This result collectively suggests that doped TiO 2 is a potential, inexpensive material for high-performance lithium-ion batteries that enable both fast charging and high energy storage.