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Title: Extremely Stable Sodium Metal Batteries Enabled by Localized High-Concentration Electrolytes

Abstract

Sodium (Na) metal is a promising anode for Na ion batteries. However, the high reactivity of Na metal with electrolytes and the low Na metal cycling efficiency have limited its practical application in rechargeable Na metal batteries. High concentration electrolytes (HCE, ≥4 M) consisting of sodium bis(fluorosulfonyl)imide (NaFSI) and ether solvent could ensure the stable cycling of Na metal with high coulombic efficiency, but suffer from high viscosity, poor wetting ability, and high salt cost. Here, we report that the salt concentration could be significantly reduced (≤ 1.5 M) by diluting with a hydrofluoroether (HFE) as ‘inert’ diluent, which maintains the solvation structures of HCE, thereby forming a localized high concentration electrolyte (LHCE). A LHCE (2.1 M NaFSI/DME-BTFE (solvent molar ratio 1:2)) has been demonstrated to enable the dendrite-free Na deposition with high coulombic efficiency of > 99%, fast-charging (20C) and stable cycling (90.8% retention after 40,000 cycles) of Na||Na3V2(PO4)3 batteries.

Authors:
ORCiD logo [1];  [1];  [1];  [1]; ORCiD logo [2]; ORCiD logo [1]
  1. Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States
  2. Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, United States
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
OSTI Identifier:
1439030
Report Number(s):
PNNL-SA-130233
Journal ID: ISSN 2380-8195; 49321; VT1201000
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
ACS Energy Letters
Additional Journal Information:
Journal Volume: 3; Journal Issue: 2; Journal ID: ISSN 2380-8195
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
Sodium metal battery; concentrated electrolyte; diluent; high coulombic efficiency; fast charging; Environmental Molecular Sciences Laboratory

Citation Formats

Zheng, Jianming, Chen, Shuru, Zhao, Wengao, Song, Junhua, Engelhard, Mark H., and Zhang, Ji-Guang. Extremely Stable Sodium Metal Batteries Enabled by Localized High-Concentration Electrolytes. United States: N. p., 2018. Web. doi:10.1021/acsenergylett.7b01213.
Zheng, Jianming, Chen, Shuru, Zhao, Wengao, Song, Junhua, Engelhard, Mark H., & Zhang, Ji-Guang. Extremely Stable Sodium Metal Batteries Enabled by Localized High-Concentration Electrolytes. United States. doi:10.1021/acsenergylett.7b01213.
Zheng, Jianming, Chen, Shuru, Zhao, Wengao, Song, Junhua, Engelhard, Mark H., and Zhang, Ji-Guang. Tue . "Extremely Stable Sodium Metal Batteries Enabled by Localized High-Concentration Electrolytes". United States. doi:10.1021/acsenergylett.7b01213.
@article{osti_1439030,
title = {Extremely Stable Sodium Metal Batteries Enabled by Localized High-Concentration Electrolytes},
author = {Zheng, Jianming and Chen, Shuru and Zhao, Wengao and Song, Junhua and Engelhard, Mark H. and Zhang, Ji-Guang},
abstractNote = {Sodium (Na) metal is a promising anode for Na ion batteries. However, the high reactivity of Na metal with electrolytes and the low Na metal cycling efficiency have limited its practical application in rechargeable Na metal batteries. High concentration electrolytes (HCE, ≥4 M) consisting of sodium bis(fluorosulfonyl)imide (NaFSI) and ether solvent could ensure the stable cycling of Na metal with high coulombic efficiency, but suffer from high viscosity, poor wetting ability, and high salt cost. Here, we report that the salt concentration could be significantly reduced (≤ 1.5 M) by diluting with a hydrofluoroether (HFE) as ‘inert’ diluent, which maintains the solvation structures of HCE, thereby forming a localized high concentration electrolyte (LHCE). A LHCE (2.1 M NaFSI/DME-BTFE (solvent molar ratio 1:2)) has been demonstrated to enable the dendrite-free Na deposition with high coulombic efficiency of > 99%, fast-charging (20C) and stable cycling (90.8% retention after 40,000 cycles) of Na||Na3V2(PO4)3 batteries.},
doi = {10.1021/acsenergylett.7b01213},
journal = {ACS Energy Letters},
issn = {2380-8195},
number = 2,
volume = 3,
place = {United States},
year = {2018},
month = {1}
}