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Understanding Electrochemical Reaction Mechanisms of Sulfur in All-Solid-State Batteries through Operando and Theoretical Studies ** |
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| Authors: | Daxian Cao Xiao Sun Fei Li Seong-Min Bak Tongtai Ji Michael Geiwitz Kenneth S. Burch Yonghua Du Guochun Yang Hongli Zhu |
| Affiliation: | 1. Department of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115 USA;2. Department of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115 USA These authors contributed equally to this work. Contribution: Conceptualization (equal), Data curation (equal), Investigation (equal), Validation (lead), Writing - original draft (equal), Writing - review & editing (equal);3. State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao, 066004 China These authors contributed equally to this work. Contribution: Investigation (equal), Software (equal), Writing - original draft (equal), Writing - review & editing (equal);4. National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973 USA Contribution: Data curation (supporting), Resources (lead);5. Department of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115 USA Contribution: Investigation (supporting), Writing - review & editing (supporting);6. Department of Physics, Boston College, 140 Commonwealth Ave, Chestnut Hill, MA, 02467-3804 USA Contribution: Resources (equal);7. Department of Physics, Boston College, 140 Commonwealth Ave, Chestnut Hill, MA, 02467-3804 USA Contribution: Resources (lead);8. State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao, 066004 China |
| Abstract: | Due to its outstanding safety and high energy density, all-solid-state lithium-sulfur batteries (ASLSBs) are considered as a potential future energy storage technology. The electrochemical reaction pathway in ASLSBs with inorganic solid-state electrolytes is different from Li-S batteries with liquid electrolytes, but the mechanism remains unclear. By combining operando Raman spectroscopy and ex situ X-ray absorption spectroscopy, we investigated the reaction mechanism of sulfur (S8) in ASLSBs. Our results revealed that no Li2S8, Li2S6, and Li2S4 were formed, yet Li2S2 was detected. Furthermore, first-principles structural calculations were employed to disclose the formation energy of solid state Li2Sn (1≤n≤8), in which Li2S2 was a metastable phase, consistent with experimental observations. Meanwhile, partial S8 and Li2S2 remained at the full lithiation stage, suggesting incomplete reaction due to sluggish reaction kinetics in ASLSBs. |
| Keywords: | All-Solid-State Lithium-Sulfur Batteries Operando Raman Spectroscopy Solid-State Reactions Sulfur X-Ray Absorption Spectroscopy |