First-principles study of electronic structure, sodium diffusion on 2D TiO2 monolayers for sodium-ion battery electrodes

The search for suitable electrode materials is crucial for the development of high-performance Na-ion batteries (NIBs). In recent years, significant attention has been drawn to two-dimensional (2D) oxides as potential NIB electrode materials. In this study, employing the first-principles density functional theory method, we investigate the thermodynamic and kinetic properties of Na adsorption and diffusion behavior on the 2D TiO2(010) monolayer. Our findings demonstrate that the 2D anatase TiO2(010) monolayer exhibits enhanced thermodynamic stability. Furthermore, the Na atoms preferentially adsorb on the top of oxygen atoms within the TiO2(010) monolayer, and their diffusion along the [100] direction is characterized by a low energy barrier of 0.054 eV. This comprehensive analysis sheds light on the structural stability, preferred adsorption sites, and diffusion paths of Na atoms on the 2D anatase TiO2(010) monolayer, providing valuable insights into the nature of the material's structure and Na ion transport. Moreover, the 2D structure of the TiO2matrix facilitates short Na diffusion lengths and a large electrode/electrolyte interface, thereby demonstrating the potential of this material as an NIB electrode material.