The first part of the talk will discuss the emerging solvate electrolytes as possible electrolyte solutions for Li-S batteries. The solvate electrolytes are characterized by extremely high quantities of salt resulting in interesting electrochemistry at the S cathode. Because the behavior of the electrolyte solution is governed by the complexes in the solution, we will explore the local solvation structure of the active cation, Li⁺, and how it is affected by the addition of what are commonly thought to be innocuous cosolvents. The addition of the cosolvents to the solvate electrolyte results in subtle but important changes in the Li⁺ solvation structure that affect the kinetics of the S reduction.

The second part of the talk will focus on electrolytes for Mg batteries. We will explore the local structure of Mg²⁺ in the seemingly simple MgCl₂ + AlCl₃ in THF electrolyte known as the magnesium aluminum chloride complex (MACC) electrolyte. The importance of Mg speciation in active electrolytes and the effect these complexes have on the charge transfer processes at the electrode-electrolyte interface will be addressed. We will also explore the role of chloride in facilitating the electrodeposition of divalent Mg²⁺ and the implications of using halogenated electrolytes in full cells.