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Computational Insights into Mg‐Cl Complex Electrolytes for Rechargeable Magnesium Batteries
Author(s) -
Moss Jared B.,
Zhang Liping,
Nielson Kevin V.,
Bi Yujing,
Wu Chao,
Scheiner Steve,
Liu T. Leo
Publication year - 2019
Publication title -
batteries and supercaps
Language(s) - English
Resource type - Journals
ISSN - 2566-6223
DOI - 10.1002/batt.201900029
Subject(s) - tetrahydrofuran , chemistry , magnesium , solvation , electrolyte , inorganic chemistry , isomerization , octahedron , medicinal chemistry , ion , organic chemistry , catalysis , solvent , electrode
DFT calculations were conducted to provide unprecedented thermodynamic insights on tetrahydrofuran (THF) solvation, isomerization, and complexation of possible Mg−Cl coordination species for popular Mg−Cl electrolytes for magnesium batteries. Computational results using the M06‐2x functional with the 6‐31+G(d) basis set indicate that trigonal bipyramidal e,e ‐ cis‐tbp ‐MgCl 2 (THF) 3 dichloride species and octahedral [MgCl(THF) 5 ] + monochloride species are the dominant mononuclear species. These two can combine to form the dinuclear species [( μ ‐Cl) 3 Mg 2 (THF) 6 ] + with a free energy −6.30 kcal/mol, which is calculated to be the dominant Mg−Cl species in solution. Two mono‐cation species, [( μ ‐Cl) 3 Mg 2 (THF) 6 ] + and [MgCl(THF) 5 ] + , have comparable LUMO energies, thus both of them can act as active species for Mg deposition. However, the significant dominance of the dinuclear species in the electrolyte indicates that it is the primary species involved in reversible Mg deposition.