Monolayer α-Tellurene as Anode for Metal Ion Rechargeable Batteries: A Comprehensive Investigation through DFT and AIMD Studies

Herein, we have performed combined density functional theory (DFT) and ab initio molecular dynamics (AIMD) calculations to investigate the potential of α-tellurene (α-Te) monolayer as anode materials for metal ion batteries. Initial investigations explore the adsorption of lithium(Li)/sodium(Na)/magnesium(Mg) ions and their diffusion on α-Te anode. The Li-ion showed higher adsorption energy (−2.21 eV) compared to Na and Mg ions. The diffusion barrier of Li and Na is found to be 0.23 and 0.17 eV, respectively, compared to the Mg ion (0.53 eV). To understand the electrolyte–electrode interface characteristics, Li salt electrolytes with bis(fluorosulfonyl) imide (FSI) and bis-trifluoromethane sulfonyl imide (TFSI) anions are made to interact in parallel and perpendicular orientations with the surface of the α-Te anode. The adsorption of both FSI and TFSI anions is energetically favorable, and it induces a semiconductor-to-metal transition in the anode. Furthermore, the AIMD study on Li+ integrated FSI/TFSI anions with α-Te was performed to understand the structural and dynamical parameters including the radial distribution function (RDF), diffusivity, etc. The α-Te monolayer has retained its structural integrity throughout the simulations. The RDF plots confirm that the oxygen of FSI and TFSI are more aggregating around the Li ions forming the solvation shell that initiates ion migration. Also, the pathway of Li+ ion migration through the anions involves both vehicular and structural diffusion mechanisms. The self-diffusion coefficient of Li-ion is calculated as 4.48 × 10–9 m2/s and 3.05 × 10–9 m2/s in FSI and TFSI systems, respectively. In summary, our results demonstrate that the α-Te monolayer can be regarded as a reliable anode with excellent ion diffusion for future metal ion rechargeable batteries.