| AVS 62nd International Symposium & Exhibition | |
| In-Situ Spectroscopy and Microscopy Focus Topic | Tuesday Sessions |
| Session IS-TuP |
| Session: | In-Situ Spectroscopy and Microscopy Poster Session |
| Presenter: | Murugesan Vijayakumar, Pacific Northwest National Laboratory |
| Authors: | V. Shutthanandan, Pacific Northwest National Laboratory M.I. Nandasiri, Pacific Northwest National Laboratory A. Schwarz, Pacific Northwest National Laboratory T.C. Kaspar, Pacific Northwest National Laboratory S.A. Thevuthasan, Qatar Environment and Energy Research Institute, Qatar M. Vijayakumar, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
The interaction between a charged surface (i.e. electrode) and an ionic solution (i.e. electrolyte) is the basic science that drives various systems ranging from biological membranes to energy storage and conversion devices. In a typical electrode-electrolyte interfacial region, ions from the electrolyte can form an electric-dipole with oppositely charged electrode and subsequently produce an electric double layer (EDL). This EDL formation is a highly reversible process that involves no chemical/phase changes and is widely used in modern devices such as chemical sensors, field-effect transistors and supercapacitors. However, a clear understating of the impact of the electrode surface chemistry and the nature of electrolyte ions on molecular structure-property relationship at modern interfaces is still lacking. One of the unique features of these interfaces is that they contain non-equilibrium ion concentration under biased conditions. A multilayer formation with alternative charges (i.e., cation/anion) is expected under charged conditions, which can subsequently result in gradient change in ion concentration depend on the applied potential. To clearly distinguish the role of each electrode/electrolyte parameter under charging conditions, an unique in-situ angle-resolved X-ray photoelectron spectroscopy (AR-XPS) setup was developed at the Environmental Molecular Sciences Laboratory (EMSL) in Pacific Northwest National Laboratory. The change in composition of Ionic liquid electrolyte and specifically cation/anion ratio at different charging conditions was analyzed as a function of depth using in-situ AR-XPS. Preliminary results obtained from a model system consisted of porous carbon electrode and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid electrolyte will be discussed here. In addition, the derived depth-profile information (such as surface adsorption and multilayer formation) will be compared with the number density profiles of cation/anions calculated from the optimized MD simulations.