Salt Concentration Effects on Water and Ion Diffusivities in Aqueous Sodium Ion Battery Electrolyte Aditya Wibawa Sakti(a*), Setyanto Tri Wahyudi(b), Faozan Ahmad(b), Noviyan Darmawan(b), Hendradi Hardhienata(b), Husin Alatas(b)
a) Global Center for Science and Engineering, Waseda University, Japan
* aditya[at]aoni.waseda.jp
b) Departemen Fisika, Institut Pertanian Bogor, Indonesia
Abstract
Sodium-ion battery is a promising alternative to the well-known lithium-ion battery, owing to the large abundance of sodium ion as it can be found directly from the ocean. To further increase the safety aspect of the sodium-ion battery, the aqueous-based electrolyte has been developed. Ion and water diffusivities is one of the most essential properties that have to be considered in developing a good quality electrolytes. To estimate the diffusion coefficient theoretically, the quantum-mechanical(QM)-based molecular dynamics simulations have been performed. During the diffusion process, the overlapping orbitals and orbital polarizations are at play, thus classical molecular dynamics simulation is not sufficient to describe this type of diffusion. In the present work, we employed the density-functional tight-binding (DFTB) method to handle molecular dynamics simulations that contains more than 1000 atoms in the simulated systems. The present work shows that the water and ion diffusions become slower at high salt concentration.
