Transport Number Determination and Relevance for Lithium Metal Batteries Using Localized Highly Concentrated Electrolytes
Artikel i vetenskaplig tidskrift, 2025

The lithium transport number (t(Li)(+)) determination of fluorinated ether (1,2-(1,1,2,2-tetrafluoroethoxy) ethane, TFEE)-based localized highly concentrated electrolytes (LHCEs) with 1,2-dioxolane (DOL) and dimethoxyethane (DME) as solvents has been explored using molecular dynamics simulations, nuclear magnetic resonance spectroscopy, Bruce-Vincent's method, and low-frequency electrochemical impedance spectroscopy (EIS). We showcase that the TFEE-DOL LHCE has a t(Li)(+) as high as 0.65 but, on the other hand, exhibits low Coulombic efficiency (<90%) and poor stability vs Li metal anodes, i.e., in a lithium metal battery (LMB) setting. In contrast, the TFEE-DME LHCE shows high Coulombic efficiency (98.9%) and stability, despite a much lower t(Li)(+) (0.25). A significant migration resistance through the porous solid electrolyte interphase (SEI) for the former is the likely explanation, as revealed by EIS and assisted by scanning electron microscopy and X-ray photoelectron spectroscopy experiments. We thus find the interfacial properties at the Li metal anode to be more crucial than the ionic transport through the bulk of the electrolyte for LMB performance. We therefore propose that the focus should be put on the full (operando) impedance spectra of Li metal anodes in contact with electrolytes, since it enables the characterization of the interphase layer(s), rather than solely determining the (bulk) t(Li)(+) of the electrolytes.

Ions

Electrolytes

Metals

Surface chemistry

Electrodes

Författare

Hafiz Ahmad Ishfaq

Alistore - European Research Institute

Kemijski Inštitut

Univerza V Ljubljani

Carolina Cruz Cardona

Chalmers, Fysik, Materialfysik

Elena Tchernychova

Kemijski Inštitut

Patrik Johansson

Alistore - European Research Institute

Chalmers, Fysik, Materialfysik

Miran Gaberscek

Univerza V Ljubljani

Kemijski Inštitut

Robert Dominko

Alistore - European Research Institute

Kemijski Inštitut

Univerza V Ljubljani

Sara Drvaric Talian

Kemijski Inštitut

Chemistry of Materials

0897-4756 (ISSN) 1520-5002 (eISSN)

Vol. In Press

Nästa generations batterier

Vetenskapsrådet (VR) (2021-00613), 2021-12-01 -- 2032-12-31.

Ämneskategorier (SSIF 2025)

Materialkemi

Oorganisk kemi

Fysikalisk kemi

DOI

10.1021/acs.chemmater.4c03067

Mer information

Senast uppdaterat

2025-03-27