Toshihiko Mandai

Criteria for solvate ionic liquids

Certain concentrated mixtures of salts and solvents are not simply solutions anymore, but they may be described as ionic liquids. In this perspective paper, we describe possible criteria for the new family of ionic liquids: solvate ionic liquids. This subclass of ionic liquids was originally proposed by Angell et al. in their recent review; however, their criteria remain to be debated. Concentrated mixtures of lithium salts and organic solvents are useful models for these solvate ionic liquids, and the effects of the salt concentration, types of solvents, and counter anions of the lithium salts on their structure and properties have been explored to enable contrast with traditional solutions, and to help determine whether a given mixture belongs to the solvate ionic liquid or not.

A key concept of utilization of both non-Grignard magnesium chloride and imide salts for rechargeable Mg battery electrolytes

The utility of both non-Grignard magnesium chloride and imide salts for rechargeable magnesium battery electrolytes with an enhanced thermal stability has been demonstrated. Electrochemical characterization along with crystallography and Raman spectroscopy revealed the structure of the magnesium compounds responsible for the electrochemical activity of these electrolytes.

Solvate Ionic Liquids for Li, Na, K, and Mg Batteries

From the viewpoint of element strategy, non-Li batteries with promising negative and positive electrodes have been widely studied to support a sustainable society. To develop non-Li batteries having high energy density, research on electrolyte materials is pivotal. Solvate ionic liquids (SILs) are an emerging class of electrolytes possessing somewhat superior properties for battery applications compared to conventional ionic liquid electrolytes. In this account, we describe our recent efforts regarding SIL-based electrolytes for Li, Na, K, and Mg batteries with respect to structural, physicochemical, and electrochemical characteristics. Systematic studies based on crystallography and Raman spectroscopy combined with thermal/electrochemical stability analysis showed that the balance of competitive cation-anion and cation-solvent interactions predominates the stability of the solvate cations. We also demonstrated battery applications of SILs as electrolytes for non-Li batteries, particularly for Na batteries.