Low-Concentrated Lithium Hexafluorophosphate Ternary-based Electrolyte for a Reliable and Safe NMC/Graphite Lithium-Ion Battery

Current commercial lithium-ion battery (LIB) electrolytes are heavily influenced by the cost, chemical instability, and thermal decomposition of the lithium hexafluorophosphate salt (LiPF6). This work studies the use of an unprecedently low Li salt concentration in a novel electrolyte, which shows e...

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Bibliographic Details
Published in:The journal of physical chemistry letters 2021-02, Vol.12 (7), p.1911-1917
Main Authors: Nikiforidis, Georgios, Raghibi, Mohamed, Sayegh, Adnan, Anouti, Mérièm
Format: Article
Language:English
Subjects:
Physical Insights into Energy Science
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Summary:Current commercial lithium-ion battery (LIB) electrolytes are heavily influenced by the cost, chemical instability, and thermal decomposition of the lithium hexafluorophosphate salt (LiPF6). This work studies the use of an unprecedently low Li salt concentration in a novel electrolyte, which shows equivalent capabilities to their commercial counterparts. Herein, the use of 0.1 M LiPF6 in a ternary solvent mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (TFE) (3EC/7EMC/20TFE, by weight) is investigated for the first time in LiNi1/3Mn1/3Co1/3O2 (NMC111)/graphite pouch cells. In solution, the Li+ transport number and diffusion are governed by the Grotthuss mechanism, with transport properties being independent of salt concentration. The proposed electrolyte operates in a wide temperature window (0–40 °C), is nonflammable (self-extinguishing under 2 s), and shows adequately fast wetting (4 s). When incorporated into the NMC/graphite pouch cell, it initially forms a solid electrolyte interphase (SEI) with minimal gas formation followed by a comparable battery performance to standard LiPF6 electrolytes, validated by a high specific capacity of 165 mAh g–1, Coulombic efficiencies of 99.3%, and capacity retention of 85% over 700 cycles.
ISSN:1948-7185
1948-7185
DOI:10.1021/acs.jpclett.0c03736