Electrolytes with moderate lithium polysulfide solubility for high-performance long-calendar-life lithium–sulfur batteries

Journal Article · Mon Jul 24 00:00:00 EDT 2023 · Proceedings of the National Academy of Sciences of the United States of America

DOI:https://doi.org/10.1073/pnas.2301260120· OSTI ID:1992166

Gao, Xin ^[1]; Yu, Zhiao ^[2]; Wang, Jingyang ^[1]; Zheng, Xueli ^[3]; Ye, Yusheng  ^[1]; Gong, Huaxin  ^[4]; Xiao, Xin ^[1]; Yang, Yufei ^[1]; Chen, Yuelang ^[2]; Bone, Sharon E. ^[5]; Greenburg, Louisa C. ^[1]; Zhang, Pu  ^[1]; Su, Hance  ^[1]; Affeld, Jordan ^[1]; Bao, Zhenan  ^[4]; Cui, Yi ^[3]

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1. Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305
2. Department of Chemical Engineering, Stanford University, Stanford, CA 94305, Department of Chemistry, Stanford University, Stanford, CA 94305
3. Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA 94025
4. Department of Chemical Engineering, Stanford University, Stanford, CA 94305
5. Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025

Lithium–sulfur (Li-S) batteries with high energy density and low cost are promising for next-generation energy storage. However, their cycling stability is plagued by the high solubility of lithium polysulfide (LiPS) intermediates, causing fast capacity decay and severe self-discharge. Exploring electrolytes with low LiPS solubility has shown promising results toward addressing these challenges. However, here, we report that electrolytes with moderate LiPS solubility are more effective for simultaneously limiting the shuttling effect and achieving good Li-S reaction kinetics. We explored a range of solubility from 37 to 1,100 mM (based on S atom, [S]) and found that a moderate solubility from 50 to 200 mM [S] performed the best. Using a series of electrolyte solvents with various degrees of fluorination, we formulated the S ingle- S olvent, S ingle- S alt, S tandard S alt concentration with M oderate L i PSs so l ubility E lectrolytes (termed S ₆ MILE ) for Li-S batteries. Among the designed electrolytes, Li-S cells using fluorinated-1,2-diethoxyethane S ₆ MILE (F4DEE-S ₆ MILE) showed the highest capacity of 1,160 mAh g ⁻¹ at 0.05 C at room temperature. At 60 °C, fluorinated-1,4-dimethoxybutane S ₆ MILE (F4DMB-S ₆ MILE) gave the highest capacity of 1,526 mAh g ⁻¹ at 0.05 C and an average CE of 99.89% for 150 cycles at 0.2 C under lean electrolyte conditions. This is a fivefold increase in cycle life compared with other conventional ether-based electrolytes. Moreover, we observed a long calendar aging life, with a capacity increase/recovery of 4.3% after resting for 30 d using F4DMB-S ₆ MILE. Furthermore, the correlation between LiPS solubility, degree of fluorination of the electrolyte solvent, and battery performance was systematically investigated.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Vehicle Technologies Office (VTO); USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
• Grant/Contract Number: Battery500; AC02-76SF00515; ECCS-2026822
• OSTI ID: 1992166
• Alternate ID(s): OSTI ID: 1997531
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Vol. 120 Journal Issue: 31; ISSN 0027-8424
• Publisher: Proceedings of the National Academy of Sciences
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
Li-S batteries
electrolyte engineering
moderate polysulfide solubility
long calender life