Investigating the Role of Crown Ethers in Enhancing Metal Cation Solvation and Diffusion in Lithium and Sodium-Based Electrolytes

Abstract

The use of electrolyte additive in battery chemistry is emerging field of research towards the improvement of ion transport and solid-electrolyte-interface formation. The crown ethers are an important class of macrocyclic ligands which display a conspicuous selectivity to metal ions based on the host-guest interaction. Crown ethers are cyclic compounds with a cavity that can selectively bind metal cations like lithium and sodium. This ability to encapsulate specific cations helps in controlling ion transport, which is critical in batteries like lithium-ion batteries (LIBs) or sodium-ion batteries (SIBs). By complexing with metal cations, crown ethers can improve the mobility of ions within the electrolyte. This can lead to better ionic conductivity, enhancing battery efficiency and performance. In our work we have introduced the different crown ethers like 12C4, 15C5 and 18C6 as an electrolyte additive with boron based additive electrolyte in the presence of lithium as well as sodium salt and organic solvent electrolyte to understand the solvation as well as diffusion phenomena of metal cation. The results obtained from the atomistic molecular dynamics simulation approach revealed that the intercation of metal cation with the crown ether plays a prominent role in the diffusion and solvation properties in battery. With increase in the size of crown ether the diffusion of itself decreases. This results in decreasing the diffusion of metal cation with increase in the size of crown ethers which follows the reduction in transport properties