A Comparative Analysis of Molecular Interactions and Ion Transport Between Dextrose and L‐Tyrosine in Ethaline‐ <scp>DES</scp> for Li‐Ion Batteries

ABSTRACT Deep eutectic solvents (DESs) are emerging as sustainable electrolytes for Li‐ion batteries, yet their performance is fundamentally governed by complex molecular interactions. In this work, we present a comparative study of two bio‐additives, dextrose and L‐tyrosine, in ethaline‐DES to understand their influence on transport properties. Experimental density, viscosity, and ionic conductivity measurements, supported by Walden analysis, revealed that L‐tyrosine induces a significant positive deviation from ideality, indicating enhanced ion dissociation compared to dextrose. Computational modeling provided a molecular‐level explanation for these observations. DFT calculations demonstrated that the formation of Lithium salt‐additive complexes is thermodynamically spontaneous and stabilized by strong hydrogen bonding. Crucially, Molecular Dynamics (MD) simulations establish that L‐tyrosine forms a significantly more compact and rigid primary solvation shell around the Li cation compared to the broader coordination of dextrose. This targeted, rigid steric shielding effectively isolates the lithium cation from the perchlorate anion, suppressing ion‐pairing and improving the lithium transport number. By correlating macroscopic transport properties with molecular‐level insights, this work establishes L‐tyrosine as a superior additive for designing safer and more efficient DES‐based electrolytes.