Anomalous Solubility-Inverted Behavior of LiPF₆ in Glyme Ether Solvents for High-Voltage Electrochemistry.

Authors

Huida Lyu, Kuan-Yu Lin, Haoyu Li, Hayoung Park, Min-Ho Kim, Tian-Yu Wang, Kaiyan Liang, Jiayi Yu, Dingyi Zhao, Cheng-Wei Lin, Richard B Kaner, Yuzhang Li

Published in

Journal of the American Chemical Society. Jul 27, 2026. Epub Jul 27, 2026.

Abstract

Advanced electrolyte configurations are essential for next-generation lithium batteries. Glyme ether electrolytes are attractive due to their low reactivity with lithium metal. However, the commonly used lithium bis(fluorosulfonyl)imide (LiFSI) salt exhibits poor anodic stability due to severe aluminum corrosion. In contrast, lithium hexafluorophosphate (LiPF₆) offers excellent aluminum compatibility at high voltages but exhibits abnormally low solubility in glyme ether solvents, limiting its application in lithium batteries. The underlying mechanism for this behavior remains unclear. Herein, we show that the low solubility of LiPF₆ in glyme ether solvents originates from a "dissociation-solvation-reprecipitation" mechanism. Taking LiPF₆ in dimethoxyethane (DME) as an example, weak dielectric screening and high molecular symmetry of glyme ethers promote the association of DME-solvated Li⁺ and PF₆^-, leading to the formation of an insoluble solvate crystal, Li(DME)₂PF₆. Based on this mechanism, we further predict and experimentally verify a solubility-inverted region (SIR), in which LiPF₆ and glyme ethers can reform a homogeneous solution once the LiPF₆ concentration exceeds a critical threshold, provided that the eutectic point between the Li(ether)_xPF₆ solvate crystal and LiPF₆ falls below the operating temperature. Consequently, an electrolyte consisting of 5.0 M LiPF₆ in DME/DEE (1:1 vol %) exhibits anodic stability up to 7.0 V vs Li⁺/Li. A Li||LiNi_0.8Co_0.1Mn_0.1O₂ cell with a cutoff voltage of 4.5 V further confirms the feasibility of high voltage electrochemistry in LiPF₆-glyme ether electrolytes. These results clarify LiPF₆-glyme ether interactions and offer new opportunities for designing advanced electrolytes for high-voltage LMBs.

PMID:
42504551
Bibliographic data and abstract were imported from PubMed on 27 Jul 2026.

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