Identifying the Role of Solvation Entropy for the Solvation Chemistry in Nonaqueous Electrolytes

Abstract

Solvating power, a pivotal determinant of solvation structure, has been extensively studied in past few decades. However, extant descriptors such as donor number and binding energy, predominantly focus on solvation enthalpy, while ignoring crucial solvation entropy, which often leads to contradictory conclusions. Here, we surmount this issue by exploring the relationship between the solvation thermodynamics and solvating power. It is revealed that high solvation entropy of polydentate solvents (DME, DGDME, etc.) endows them with strong solvating power in spite of their low binding energy. Even for monodentate solvents, solvation entropy is also non-negligible. Thus, solvation free energy (ΔG) is first proposed as a perfect descriptor of solvating power, which includes the effect of solvation entropy. Drawing on profound insights of solvation thermodynamics and solvating power, a database of ΔG_Avg and permittivity of common solvents is established to provide pivotal inspirations for the design of solvation structure for next-generation advanced electrolytes.