Grützke M, Mönnighoff X, Horsthemke F, Kraft V, Winter M, Nowak S
Forschungsartikel (Zeitschrift) | Peer reviewedA flow-through method for the extraction of lithium-ion battery electrolytes with supercritical and liquidcarbon dioxide (sc and liq CO2) under the addition of different solvents has been developed andoptimized to achieve quantitative extraction of the electrolyte from commercial LiNi1/3Co1/3Mn1/3O2(NMC)/graphite 18 650 cells. Furthermore, the time-dependence of the extraction procedure wasinvestigated and demonstrated. The extracts were analyzed with gas and ion chromatography. Linearcarbonates like dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC), respectively, were betterextracted with liq CO2, whereas the cyclic carbonate ethylene carbonate (EC) was recovered in higheramounts with sc CO2. The addition of solvents to the CO2 resulted in improved recovery for all theingredients but most effectively for LiPF6, which could not be obtained by extraction with CO2 only. Thebest results were achieved by extracting for 30 minutes with liq CO2 (25 C, 60 bar) and 0.5 mL min 1acetonitrile (ACN)/propylene carbonate (PC) in a mixture of three to one and an additional 20 minuteswith liq CO2 only, to yield (89.1 3.4) wt% electrolyte in almost its original composition of DMC, EMC,EC (1 : 1 : 1) with 1.1 mol L 1 LiPF6. Therefore, the presented method can be relevant for the recycling oflithium ion battery electrolytes but has to be validated for up-scaled processes. Furthermore, thesuitability of CO2 extraction as a tool for post-mortem or aging investigations of LIB electrolytes couldonce more successfully be demonstrated due to the extraction of aging products like diethyl-2,5-dioxahexane dicarboxylate (DEDOHC) from a pouch cell, which was electrochemically aged for1000 cycles at 1 C. In this context, extraction times and recovery rates were drastically improvedcompared to our previously reported static extraction experiments.
Grützke, Martin | Münster Electrochemical Energy Technology Battery Research Center (MEET) |
Horsthemke, Fabian | Münster Electrochemical Energy Technology Battery Research Center (MEET) |
Kraft, Vadim | Münster Electrochemical Energy Technology Battery Research Center (MEET) |
Mönnighoff, Xaver | Münster Electrochemical Energy Technology Battery Research Center (MEET) |
Nowak, Sascha | Münster Electrochemical Energy Technology Battery Research Center (MEET) |
Winter, Martin | Münster Electrochemical Energy Technology Battery Research Center (MEET) |