Probing the local structures of Choline-Glycine Electrolytes: Insights from ab initio simulations

Abstract

Amino acid ionic liquids have garnered significant attention for their potential in electrochemical energy storage due to their wide electrochemical stability windows and inherent safety. The performance of ChGly as an electrolyte for supercapacitors has been compared to that of highly efficient conventional ionic liquids. However, a thorough understanding of the microstructural characteristics responsible for the enhanced properties of ChGly aqueous solutions remains largely unexplored. In this study, ab initio molecular dynamics simulations were employed to investigate the energetic, structural, transport and spectroscopic properties of ChGly-based pure and aqueous electrolytes. A comprehensive analysis of the cation–anion and water-ion hydrogen bonding was conducted for both electrolyte systems. Structural features were examined using radial and spatial distribution functions, while the vibrational power spectra were analyzed to identify significant differences in intermolecular interactions between pure and aqueous electrolytes, stemming from modified solvation shell structures. The findings presented in this work shed light on crucial structural and spectroscopic distinctions between pure and aqueous ChGly electrolytes, providing valuable insights for further advancements in the field.