Christopher Behling , Janik Lüchtefeld , Karl J.J. Mayrhofer , Balázs B. Berkes
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引用次数: 0
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.
期刊介绍:
Electrochemistry Communications is an open access journal providing fast dissemination of short communications, full communications and mini reviews covering the whole field of electrochemistry which merit urgent publication. Short communications are limited to a maximum of 20,000 characters (including spaces) while full communications and mini reviews are limited to 25,000 characters (including spaces). Supplementary information is permitted for full communications and mini reviews but not for short communications. We aim to be the fastest journal in electrochemistry for these types of papers.