Uncharted Waters: Super-Concentrated Electrolytes

The traditional efforts in electrolytes have been mostly evolving around the “1 M” region, where maximum ion conductivities occur in the majority of non-aqueous electrolyte systems. However, recent deviation from this “optimum” concentration has revealed to us that there is a new world. In the super-concentrated regions, the reversed salt/solvent ratio brought dramatic changes in bulk liquid structures, ion transport, and interfacial and interphasial properties. Some of these unusual properties have been found to introduce benefits to electrochemical, thermal, transport, interfacial, and interphasial properties that are of significant interest to the electrochemical energy storage community. This article provides a comprehensive overview on this newly discovered and under-explored realm.