Research Topics

Ion Solvation Structure and Dynamics at Heterogenous Interfaces:

Using classical molecular dynamics, we model the manner in which the solvation environment for lithium ions changes as a function of distance from the interface.  We have found that at inorganic surfaces, the solvation environment becomes saltier and the lithium dynamics slow down considerably; both of these observations have implications for reactions at the electrode interface.  We are currently exploring the impact of the interface on co-solvent preferences in the solvation structure for binary electrolytes.

Salt Association vs. Ion Chelation for Sodium Electrolytes:

We are collaborating with Prof. Daniel Kuroda and Prof. Revati Kumar from Louisiana State University to understand the impact of chelation on ion pairing in sodium electrolytes using FT-IR experiments and computational modeling.  The glyme solvent molecules are ethers capable of binding cations, however we have shown that this chelating ability changes as a function of glyme length.  As the glymes become longer, their chelating power increases and favors ion dissociation.  This effect has been studied in conjunction with changing salt concentration.  In general we have shown that higher salt concentration favors greater ion association.  Extension of this work to consider different anions and mixtures of glymes is ongoing.

Enhanced Sampling of Ion Transport:

We are not just interested in electrolyte structure, but also how structure impacts ion transport as metal ions are transferred from the electrolyte to an intercalation electrode.  As the figure on the left shows, ion motion tends to become constrained at the interface and hinders exploration of the surface morphology.  We are currently developing new methods to address this challenge.

Electron Transport at Interfaces:

The transfer of charges at the interface includes electrons as well as ions.  We are currently developing a theoretical framework for describing electron transfer based on ensemble scattering theory that is capable of describing electron transport in fully quantum settings as well as mixed quantum/classical representations.  For condensed phases, this approach yields force expressions on electrochemical species that allow them to transition from one charge state to another.