Quantitative evaluation of LiPF6 as corrosion inhibiting additive for Al in LiTFSI-based battery electrolytes – An on-line mass spectrometric study

Behling C, Lüchtefeld J, Mayrhofer KJ, Berkes BB (2024)

Publication Type: Journal article

Publication year: 2024

Journal

Electrochemistry Communications Elsevier

Book Volume: 159

Article Number: 107646

DOI: 10.1016/j.elecom.2023.107646

Abstract

Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is a promising candidate for future lithium-ion battery (LIB) electrolytes because of its increased stability and ionic conductivity. One major drawback of this salt, however, is its ability to dissolve Al, leading to a degradation of current collectors in LIBs over time. Surface passivating additives can reduce or even completely suppress the dissolution. A truly cost and material-efficient suppression, however, can only be achieved by identifying the ideal (i.e., minimal) amount of additive. Therefore, quantifying the dissolution-suppressing effect of additives is necessary to create an optimum electrolyte mixture. In this work, we examine the influence of lithium hexafluorophosphate (LiPF6) addition to LiTFSI-based electrolytes via cyclic voltammetry (CV) in an electroanalytical flow cell (EFC) coupled on-line to an inductively coupled plasma mass spectrometer (ICP-MS) for continuous downstream elemental analysis. This setup allows the potential resolved quantification of Al dissolution with unprecedented precision in real-time. With that, we found that already very small amounts of 0.02 M LiPF6 added to 0.98 M LiTFSI will drastically reduce the total dissolved amount of Al during one CV cycle by a factor of ∼ 20, while electrolytes containing 0.30 M LiPF6 (and 0.70 M LiTFSI) completely suppress the dissolution of Al. These findings allow the substitution of large portions of LiPF6, enabling the production of safer LIBs without risking current collector degradation.

Involved external institutions

Forschungszentrum Jülich / Research Centre Jülich (FZJ) DE Germany (DE)

How to cite

APA:

Behling, C., Lüchtefeld, J., Mayrhofer, K.J., & Berkes, B.B. (2024). Quantitative evaluation of LiPF6 as corrosion inhibiting additive for Al in LiTFSI-based battery electrolytes – An on-line mass spectrometric study. Electrochemistry Communications, 159. https://doi.org/10.1016/j.elecom.2023.107646

MLA:

Behling, Christopher, et al. "Quantitative evaluation of LiPF6 as corrosion inhibiting additive for Al in LiTFSI-based battery electrolytes – An on-line mass spectrometric study." Electrochemistry Communications 159 (2024).

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