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Title: In Situ Engineering of Inorganic‐Rich Solid Electrolyte Interphases via Anion Choice Enables Stable, Lithium Anodes

The discovery of liquid battery electrolytes that facilitate the formation of stable solid electrolyte interphases (SEIs) to mitigate dendrite formation is imperative to enable lithium anodes in next‐generation energy‐dense batteries. Compared to traditional electrolyte solvents, tetrahydrofuran (THF)‐based electrolyte systems have demonstrated great success in enabling high‐stability lithium anodes by encouraging the decomposition of anions (instead of organic solvent) and thus generating inorganic‐rich SEIs. Herein, by employing a variety of different lithium salts (i.e., LiPF6,LiTFSI, LiFSI, and LiDFOB), it is demonstrated that electrolyte anions modulate the inorganic composition and resulting properties of the SEI. Through novel analytical time‐of‐flight secondary‐ion mass spectrometry methods, such as hierarchical clustering of depth profiles and compositional analysis using integrated yields, the chemical composition and morphology of the SEIs generated from each electrolyte system are examined. Notably, the LiDFOB electrolyte provides an exceptionally stable system to enable lithium anodes, delivering >1500 cycles at a current density of 0.5 mAh g−1and a capacity of 0.5 mAh g−1in symmetrical cells. Furthermore, Li//LFP cells using this electrolyte demonstrate high‐rate, reversible lithium storage, supplying 139 mAh g(LFP)−1at C/2 (≈0.991 mAh cm−2, @ 0.61 mA cm−2) with 87.5% capacity retention over 300 cycles (average Coulombic efficiency >99.86%).

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Author(s) / Creator(s):
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Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Advanced Materials
Medium: X
Sponsoring Org:
National Science Foundation
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    This work was partially supported by the U.S. National Science Foundation (NSF) Award No. ECCS-1931088. S.L. and H.W.S. acknowledge the support from the Improvement of Measurement Standards and Technology for Mechanical Metrology (Grant No. 22011044) by KRISS.

    Figure 1


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