| AVS 63rd International Symposium & Exhibition | |
| In-Situ and Operando Spectroscopy and Microscopy for Catalysts, Surfaces, & Materials Focus Topic | Thursday Sessions |
| Session IS-ThP |
| Session: | In-Situ and Operando Spectroscopy and Microscopy for Catalysts, Surfaces, & Materials Poster Session |
| Presenter: | Manjula Nandasiri, Pacific Northwest National Laboratory |
| Authors: | M.I. Nandasiri, Pacific Northwest National Laboratory A.M. Schwarz, Pacific Northwest National Laboratory V. Shutthanandan, Pacific Northwest National Laboratory P. Kandasamy, Pusan National University, Republic of Korea S.A. Thevuthasan, Qatar Environment and Energy Research Institute V. Murugesan, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
Lithium-sulfur (Li-S) battery is a promising candidate to replace Li-ion battery due to their high theoretical specific capacity and energy density. However, there are some challenges to overcome to realize the practical applications of Li-S batteries. One of the most critical challenges to overcome is the shuttling of long chain lithium polysulfides (LiPS), which results in the formation of solid-electrolyte interface (SEI) layer on the electrodes and fading of the battery capacity. The constituents and properties of the SEI layers are dependent on the electrolyte and not very well-understood. It was suggested that the application of in-situ or in-operando techniques can capture the dynamic changes in the SEI layer during the battery cycling. Thus, our aim was to study the fundamental properties of SEI layer of various electrode-electrolyte systems in their working environment using in-situ XPS and imaging XPS. In order to do that, we developed an in-situ XPS capability at Environmental Molecular Sciences Laboratory located in Pacific Northwest National Laboratory.
Analyzing the SEI layers in-situ using XPS techniques is very challenging task due to the nature of the electrolytes and their behavior in vacuum systems. Therefore, a vacuum friendly ionic liquid (1-butyl-1-methylpyrrolidinium bis(trifluoromethyl-sulfonyl)imide) was selected as the electrolyte along with Li and graphite electrodes for the in-situ XPS characterization of SEI layers. Using this in-situ configuration, we were able to determine the composition of SEI layers formed on Li anode and graphite cathode in Li/ionic liquid/graphite battery system. These XPS results show the gradual formation of LiPS compounds and the decomposition of electrolyte on Li anode with the formation of LiF during the charging and discharging process.Moreover, the elemental and chemical state distributions of SEI layer were mapped using in-situ imaging XPS. In addition, we continued the SEI layer characterization of electrodes cycled in the electrolytes which cannot be handled in vacuum using a glove box attached to the XPS system. The XPS and imaging XPS results of these studies will be extensively discussed.