Supercritical CO₂ extraction of organic carbonate-based electrolytes of lithium-ion batteries

Abstract

Supercritical fluid extraction (SFE) was applied to reclaim organic carbonate-based electrolytes of spent lithium-ion batteries. To optimize the SFE operational conditions, the response surface methodology was adopted. The parameters studied were as follow: pressure, ranging from 15 to 35 MPa; temperature, between 40 C and 50 C and static extraction time, within 45 to 75 min. The optimal conditions for extraction yield were 23 MPa, 40 C and was dynamically extracted for 45 min. Extracts were collected at a constant flow rate of 4.0 L min À1 . Under these conditions, the extraction yield was 85.07 AE 0.36%, which matched with the predicted value. Furthermore, the components of the extracts were systematically characterized and analyzed by using FT-IR, GC-MS and ICP-OES, and the effect of SFE on the electrolyte reclamation was evaluated. The results suggest that the SFE is an effective method for recovery of organic carbonate-based electrolytes from spent lithium-ion batteries, to prevent environmental pollution and resource waste.

Chromatographic Techniques in the Research Area of Lithium Ion Batteries: Current State-of-the-Art

“…In this regard, Liu et al investigated the extraction of an electrolyte (DMC, EMC, EC; 1:1:1) from a separator by static supercritical fluid extraction (SFE) [203]. The extract was afterward analyzed by GC-MS and no significant difference between the pristine electrolyte and the extract was obtained.…”

The Role of Sub- and Supercritical CO2 as “Processing Solvent” for the Recycling and Sample Preparation of Lithium Ion Battery Electrolytes

“…Dai et al described an alternative approach for the recovery of LIB electrolytes from separators with a commercial extraction system [ 162 ] ( Figure 7 ). Fourier transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), 19 F- and 31 P-NMR and inductively plasma-optical emission spectrometry (ICP-OES) were applied to systematically investigate the extract.…”

“… Schematic setup of the applied extraction procedure by Dai et al with (1) CO 2 cylinder; (2) cooling bath; (3) air driven fluid pump (gas booster pump); (4) air compressor; (5) air regulator; (6) CO 2 pressure; (7) inlet valve; (8) extraction vessel; (9) heating jacket; (10) vessel heat; (11) vent valve; (12) outlet valve; (13) flow valve; (14) valve heat; (15) heating jacket; (16) collecting vial; (17) alumina filter; and (18) gas flow meter. It was reproduced from reference [ 162 ] with permission from the Royal Society of Chemistry, 2014. …”

“… Response surfaces and contour plots for: ( a ) extraction time vs. pressure; and ( b ) extraction time vs. temperature. It was reproduced from reference [ 162 ] with permission from the Royal Society of Chemistry, 2014. …”

Graphite Recycling from Spent Lithium‐Ion Batteries

“…The recovery rates of the last two methodsinvolving highly pressurized carbon dioxide are already closely examined in literature. [8,35] Subsequently,i ron-containingp arts are removed by am agnetic separator and residual non-magnetic materials are fed to ag ravity-type zig-zaga ir classifier or cross-flow separator, where separation takes place by meanso fa ir flow into aI )fine fraction mostly containing the electrodes andI I) ac oarse fraction consisting of the separator [9] and plastics.F urthermore, the heavy fractioni st ransferred to an oven where the material is heatedt o4 00-600 8Ct od ecompose the binder,w hichi s usually based on polyvinylidene fluoride (PVdF). [10] This facilitates the detachment of the active material particles from the current collectors and from each other.T his stage is followed by as eries of air-jet sieving steps, where the active materials are detached from current collectors and separated.T he metal fraction,that is the current collectors consistingo faluminum [12] and copper, [12b] is further separatedb yd ensity differencesa nd can be disposed of at appropriate recycling facilities.…”