Temperature influence on the solvation, transport, and dielectric properties of the {NaPF₆–dimethyl sulfoxide} electrolyte system used in sodium-ion battery technology: A molecular dynamics approach and DFT study

In the current context of the energy transition, sodium-ion batteries are emerging as a promising alternative to lithium-ion batteries, mainly due to the natural abundance of sodium and its lower cost. This work focuses on the study of solvation properties, ionic mobility, and dielectric behavior of an electrolytic system composed of NaPF₆ salt, known for its high ionic conductivity and stability, dissolved in the polar aprotic solvent dimethyl sulfoxide (DMSO). The combination of two molecular simulation approaches, namely Molecular Dynamics (MD) and Density Functional Theory (DFT), allowed us to analyze these properties at various temperatures ranging from 298.15 to 373.15 K. Molecular dynamics simulations were performed using the GROMACS software, employing the OPLS-AA force field to describe the interactions between the species constituting the studied system, under atmospheric pressure and at a fixed concentration of 1 M. Furthermore, DFT calculations were carried out using the ORCA software to compare and validate the structural results obtained from the molecular dynamics approach, by computing interatomic distances, charge density on each atom, and vibrational frequencies. These calculations were performed using the B3LYP functional combined with the def2-TZVP and 6-311++G(d,p) basis sets, while solvent effects were considered through the conductor-like polarizable continuum model (CPCM). Finally, this study provided new and essential insights for the optimization of potential electrolytic systems designed for sodium-ion battery technology, thereby opening new perspectives for the development of higher-performance batteries.