Theoretical Analysis on De-Solvation of Lithium, Sodium, and Magnesium Cations to Organic Electrolyte Solvents

Abstract

De-solvation of a Li ion at an electrode/electrolyte interface can be the rate-determining step of the reaction in lithium-ion secondary batteries. The present study theoretically evaluates the de-solvation energies of Li, Na, and Mg ions to organic electrolyte solvents. The Na-ion complexes revealed commonly smaller de-solvation energies compared to the Li-ion complexes due to the weaker Lewis acidity, while the solvation structures were similar to each other. The Mg-ion complexes showed remarkably larger de-solvation energies because of the double positive charge. The increase of coordination number, which was associated with the change in the solvation structure, was observed for the Mg-ion complexes. Detailed analysis revealed good correlations between the de-solvation energies and the electrostatic potentials made by the solvents, as well as the chemical hardness of the solvents.

Experimental and Computational Analysis of the Solvent‐Dependent O2/Li+‐O2− Redox Couple: Standard Potentials, Coupling Strength, and Implications for Lithium–Oxygen Batteries

“…[12,33,38] Standard potentials were obtained by correcting extrapolated values in Figure 4 d À solubility and DN [12] (Supporting Information, Figure S12 b would not scale with DN as well, as Na + and K + are weaker Lewis acids than Li + and will be solvated less strongly. This is supported by a recent computational study of de-solvation energies of Li + and Na + in 27 organic solvents, [42] which found that Na + de-solvation energies were on average 20 % less than Li + , implying weaker Na + solvation in non-aqueous solvents. Similarly, computed gas-phase binding energies of Na + and K + to tetrahydrofuran have been reported to be much less than that for Li + , [43] [44] or trigger solution-phase growth of Li 2 O 2 , [12,16] resulting in high discharge capacities by increased pore filling with large, solid Li 2 O 2 agglomerates.…”

Understanding the Initial Stages of Reversible Mg Deposition and Stripping in Inorganic Nonaqueous Electrolytes

“…glyme, diglyme, tetraglyme, and poly-THF) is expected to inhibit Mg 2+ ion delivery at the surface. 34,35 C. THF on MgO…”

Von Lithium‐ zu Natriumionenbatterien: Vorteile, Herausforderungen und Überraschendes

“…B. eine um rund 30 %k leinere Solvatationsenergie fürN a-als fürL ithium-Ionen in verschiedenen organischen Lçsungs-mitteln berechnet. [10] Der Durchtrittswiderstand sollte daher im Falle von Natrium kleiner sein, was die Elektrodenkinetik verbessern kçnnte.…”