Molecular dynamics simulations of Li_xTiO₂ nanosphere as an anode electrode material

Materials Modelling Centre, University of Limpopo, Private Bag x1106, Sovenga, 0727, South Africa

^* Corresponding author: nkateko.rikhotso@ul.ac.za

Abstract

This study uses molecular dynamics simulations to investigate the recrystallization and thermal stability of Li_xTiO₂ nanospheres (Li_0.11TiO₂, Li_0.15TiO₂, Li_0.19TiO₂, and Li_0.23TiO₂) as potential anode materials for lithium-ion batteries. Employing the Born-Mayer-Huggins interatomic potential, the simulations examined the structural evolution of the nanospheres during temperature cycling between 0 K and 2000 K, followed by controlled cooling. The results demonstrate that Li_0.11TiO₂, Li_0.15TiO₂, and Li_0.23TiO₂ form crystalline Ti-O layers upon recrystallization, while Li_0.19TiO₂ remains amorphous. During recrystallization, Li diffusion from the core to the surface, driven by Pauli repulsion, was observed in higher-lithium-content nanospheres. Analysis of cooled structures revealed that Li_0.11TiO₂, Li_0.15TiO₂ and Li_0.23TiO₂ maintained their structural integrity and exhibited both rutile and brookite channels. Radial distribution function analysis showed a consistent Ti-O bond length of approximately 2 Å across the temperature range. The findings suggest that Li_xTiO₂ nanospheres (excluding Li_0.19TiO₂) possess promising structural stability and crystallinity at varying temperatures and lithium concentrations, making them potential anode materials for lithium-ion batteries. The presence of both rutile and brookite phases, along with Li diffusion behavior, provides valuable insights for optimizing the design of high-performance Li_xTiO₂ anodes.