Solvation–Reduction Coupling in Ca<sup>2+</sup> Electroactivity in Glyme‐Based Electrolytes: A First Principles Study
Long H. B. Nguyen, Jean‐Sébastien Filhol
Abstract
Abstract The electrochemical activity of solvated Ca 2+ in glyme‐based electrolytes is investigated using grand canonical density functional theory approach and Fukui functions. The obtained results reveal that the length of glyme molecules has little effect on the reduction potentials, but has significant impacts on the effective electron transfer process. In short chain glymes, the transferred electron is located on a Ca 2+ center and the organic part of the solvation sphere, leading to a direct Ca 2+ reduction and a partial degradation of the glyme molecules. As the glyme's length increases, the reduction process turns into the formation of solvated electrons rather than Ca 2+ reduction, unless a partial desolvation occurs. Consequently, an effective Ca 2+ reduction in long chain glyme‐based electrolytes is controlled by a (partial) desolvation of the solvation sphere. These results can be used as guiding information to design new electrolytes having the Ca 2+ reduction potential in an accessible voltage range together with an effective Ca 2+ reduction process. The methodology developed in this study can be universally applied to investigate the thermodynamic and kinetic properties of other battery systems using metal anodes, which might lead to a paradigm shift in the design of prospective electrolytes for future battery technologies.