Quantifying the influence of temperature on Al current collector dissolution in LiTFSI-based lithium-ion battery electrolytes via coupled on-line mass analysis

Abstract

This work portrays the dissolution behavior of aluminum foil current collectors in nonaqueous lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-based battery electrolytes in greater detail. This is achieved via a setup utilizing an electroanalytical flow cell (EFC) coupled to inductively coupled plasma mass spectrometry (ICP-MS), allowing unprecedented real-time analysis as well as quantification of dissolution. We show that the preparation of Aluminum foil samples drastically influences the reproducibility of measurements. Already gentle cleaning procedures will lead to tiny scratches on the oxide surface, which heavily affect the dissolution behavior of the sample. We also investigate the influence of temperature on dissolution by comparing measurements at 25, 40, and 60 °C. We show that the dissolution at 40 °C is increased by a factor of 1.5 compared to 25 °C and a factor of 3 for 60 °C, respectively. The faradaic efficiency of the Al dissolution process during cyclic voltammetric (CV) measurements is identified to be ∼ 65 – 75%.