Impact of Graphite Materials on the Consumption of Prop-1-Ene-1,3-Sultone and Vinylene Carbonate in Lithium-Ion Cells

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It has been shown that electrolyte additives can be highly beneficial to the performance and lifetime of lithium-ion cells.1,2 However, many additives are consumed in the early cycles, which will affect the cycling performance of the cell over long-term operation. It has been shown that most electrolyte additives are consumed relatively early. For example, when ≤2 wt% vinylene carbonate is used in Li[Ni0.33Mn0.33Co0.33]O2/graphite cells, most of it is consumed during the first 200 h of cell operation.3 Prop-1-ene-1,3-sultone (PES) and vinylene carbonate (VC) are among the most used electrolyte additives in lithium-ion cells. PES is useful for suppressing gas formation, and VC has been found to form a stable solid-electrolyte interphase (SEI), preventing further electrolyte decomposition on the negative electrode. The SEI formed by the decomposition of both additives on the negative electrode surface has been thoroughly characterized.4 However, the dependence between the consumption of these additives and the choice of negative electrode has not been thoroughly examined.In this work, the consumption of PES and VC was investigated in Li[Ni0.8Mn0.1Co0.1]O2/artificial graphite (NMC811/AG) or Li[Ni0.83Mn0.06Co0.11]O2/artificial graphite (Ni83/AG) pouch cells with four different artificial graphites. The physical properties of these graphite materials were reported by Eldesoky et al.5 Various amounts of VC and PES (alone or in combination with each other) between weight percentages of 0.5 to 2% were used. The cells were formed, after which the electrolytes were extracted and analyzed with quantitative GC-MS to find the amount of additives consumed.This study demonstrates the significant effect the choice of artificial graphite has on PES and VC consumption rates. In addition, the impact of varying additive amounts and using graphites with different physical properties on formation parameters such as first-cycle efficiency (FCE), charge transfer resistance (Rct), and gas production will be shown. References E. R. Logan et al., J. Electrochem. Soc., 167, 130543 (2020).T. Taskovic, L. M. Thompson, A. Eldesoky, M. D. Lumsden, and J. R. Dahn, J. Electrochem. Soc., 168, 010514 (2021).R. Petibon, J. Xia, J. C. Burns, and J. R. Dahn, J. Electrochem. Soc., 161, A1618–A1624 (2014).L. Madec et al., J. Electrochem. Soc., 162, A2635 (2015).A. Eldesoky et al., J. Electrochem. Soc., 169, 010501 (2022).