Title: Selecting the Optimal Fluorinated Ether Co-Solvent for Lithium Metal Batteries

Abstract

To guide the selection of a suitable fluorinated ether (FE) co -solvent for lithium metal batteries, it is crucial to understand the relationship between the organic structures of the FEs and the electrochemical performance of an FE-containing electrolyte. In this work, 1,1,2,2-tetrafluoro-1-(2,2,2-trifluoroethoxy)ethane (FEE), 1,1,2,2-tetrafluoro-3-(1,1,2,2-tetrafluoroethoxy)-propane (TTE), and 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane (OFDEE) were chosen as representative FE co-solvents because of their distinct structural properties. The structure-activity relationship between the FEs and the electrochemical performance of Li||LiNi_0.6Mn_0.2Co_0.2O₂ (Li||NMC622) cells was correlated and quantified by Fourier-transform infrared and multi-dimensional nuclear magnetic resonance techniques. Sand's model was also employed to assess the extent of lithium dendrite formation in the cells using various FE electrolytes. The cycling performance of Li||NMC622 cells using different FE co-solvents follows the order FEE > TTE > OFDEE. Further, since the direct measurement of Sand's time is difficult, we introduced relative Sand's time to probe the diffusion behavior of each electrolyte, and the results showed that the best performance was obtained in the electrolyte with the longest relative Sand's time. Moreover, the lithium metal cell using the electrolyte with FEE co-solvent showed similar capacity retention compared with the baseline electrolyte at room temperature, but it demonstrated significantly improved low-temperature performance. The results indicatemore » that FEE is a promising co-solvent candidate for improving the low-temperature performance of lithium metal batteries because it possesses not only non-solvating behavior but also very low viscosity and non-flammability. The advanced electrolyte LiPF₆-FEC-DMC-FEE enables very stable cycling of lithium metal batteries at various temperatures.« less

Authors:

Su, Chi-Cheung ^[1]; Amine, Khalil  ^[1];

• Search DOE PAGES for author "Amine, Khalil"
• Search DOE PAGES for ORCID "0000-0001-9206-3719"

Cai, Mei  ^[2];

• Search DOE PAGES for author "Cai, Mei"
• Search DOE PAGES for ORCID "0000-0001-8631-8471"

He, Meinan  ^[2]

• Search DOE PAGES for author "He, Meinan"
• Search DOE PAGES for ORCID "0000-0002-7747-439X"

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+ Show Author Affiliations

1. Argonne National Laboratory (ANL), Argonne, IL (United States)
2. General Motors R&D, Warren, MI (United States)

Publication Date:

Fri Jan 06 00:00:00 EST 2023

Research Org.:

Argonne National Laboratory (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Vehicle Technologies Office (VTO)

OSTI Identifier:

2217024

Grant/Contract Number:  

AC02-06CH11357

Resource Type:

Accepted Manuscript

Journal Name:

ACS Applied Materials and Interfaces

Additional Journal Information:

Journal Volume: 15; Journal Issue: 2; Journal ID: ISSN 1944-8244

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; high-voltage lithium metal batteries; lithium metal anode stabilization; fluorinated ethers; solid-electrolyte interphase; low-temperature operation