| AVS 66th International Symposium & Exhibition | |
| Surface Science Division | Friday Sessions |
| Session SS+HC+PS-FrM |
| Session: | Planetary, Ambient, and Operando Environments |
| Presenter: | Venkateshkumar Prabhakaran, Pacific Northwest National Laboratory, Joint Center for Energy Storage Research |
| Authors: | V. Prabhakaran, Pacific Northwest National Laboratory, Joint Center for Energy Storage Research S. Roy, Pacific Northwest National Laboratory, Joint Center for Energy Storage Research G.E. Johnson, Pacific Northwest National Laboratory, Joint Center for Energy Storage Research M.H. Engelhard, Pacific Northwest National Laboratory V. Shutthanandan, Pacific Northwest National Laboratory A. Martinez, Pacific Northwest National Laboratory S. Thevuthasan, Pacific Northwest National Laboratory K.T. Mueller, Pacific Northwest National Laboratory, Joint Center for Energy Storage Research V. Murugesan, Pacific Northwest National Laboratory, Joint Center for Energy Storage Research |
| Correspondent: | Click to Email |
Chemical transformations of electrolyte constituents (such as solvent and solvated electroactive ions) at the Li-metal electrode determine the evolution of the solid-electrolyte interphase (SEI). The ability to rationally design an SEI layer that will provide efficient charge transfer processes will improve the performance of Li-batteries. The main challenge is to unravel the complex set of interfacial reactions that occur during charge transfer processes and subsequently delineate the pathways of various decomposition reactions and phase formation. Herein, we report progress in understanding such complex interfaces using bottom-up assembly of solvated cations and bare anions of selected composition on Li-metal anodes. Soft landing of mass-selected ions, a versatile approach to surface modification, is ideally suited for building the interface with selected electroactive ions which will help unravel the complexity associated with the multitude of interfacial processes occurring during evolution of the SEI layer.1,2 Ion soft landing combined with operando infrared reflection-absorption spectroscopy (IRRAS) and in-situ x-ray photoelectron spectroscopy (XPS) were used to characterize the decomposition of counter anions and solvent molecules on bare Li metal surfaces. Specifically, we soft-landed isolated electrolyte anions (e.g., bis(trifluoromethane)sulfonimide, TFSI-, polysulfides, Sx-) and solvated Li solvent cluster cations (e.g. Li-(dimethoxyethane)x) on bare Li metal surfaces without their corresponding counter ions, and monitored their spontaneous decomposition using IRRAS and XPS. Our in-situ multimodal measurements captured the spectroscopic signatures of reaction pathways of the electrolyte anions and solvent molecules on the reactive Li surface. We will discuss the evolution of the SEI layer based on multimodal spectroscopic analysis of electrochemical interfaces prepared using the ion soft landing approach. In particular, the chemical signatures of transient species that evolve during decomposition at well-defined interfaces will be discussed.
References:
1. Johnson, G. E.; Hu, Q.; Laskin, J., Soft landing of complex molecules on surfaces. Annual Review of Analytical Chemistry 2011,4, 83-104.
2. Prabhakaran, V.; Johnson, G. E.; Wang, B.; Laskin, J., In situ solid-state electrochemistry of mass-selected ions at well-defined electrode–electrolyte interfaces. Proceedings of the National Academy of Sciences 2016,113, 13324-13329.